New South Wales Supreme Court CITATION : Youkhana v Di Veroli [2009] NSWSC 942 HEARING DATE(S) : 31/08/09, 01/09/09-09/09/09 JUDGMENT DATE : 14 October 2009 JUDGMENT OF : James J DECISION : Verdict for the defendants CATCHWORDS : TORT — occupier's liability — slip case — fall on stairs LEGISLATION CITED : Civil Liability Act Local Government Act 1919 Brady v Girvan Bros Pty Ltd (1986) 7 NSWLR 241 Howell v Macquarie University [2008] NSWCA 26 Jones v Dunkel (1958-59) 101 CLR 298 Malec v JC Hutton Pty Limited (1990) 169 CLR 638 CASES CITED : Manly Council v Byrne [2004] NSWCA 123 Purkess v Crittenden (1965) 114 CLR 164 Seltsam Pty Ltd v Ghaleb [2005] NSWCA 208 Watts v Rake (1960) 108 CLR 158 Wilson v Peisley (1975) 50 ALJR Lina Youkhana - Plaintiff Cesare Di Veroli - First Defendant PARTIES : Lily Di Veroli - Second Defendant Alex Di Veroli - Third Defendant Lynette Di Veroli - Fourth Defendant Limited Addition Holdings Pty Limited - Fifth Defendant FILE NUMBER(S) : SC 20139/08 COUNSEL : A J Lidden SC / M Daley - Plaintiff J Sexton SC - Defendants SOLICITORS : Bryden Solictiors - Plaintiff Moray & Agnew Solicitors - Defendants IN THE SUPREME COURT OF NEW SOUTH WALES COMMON LAW DIVISION JAMES J WEDNESDAY 14 OCTOBER 2009 20139/08 LINA YOUKHANA v CESARE DI VEROLI and ors JUDGMENT 1 HIS HONOUR: In these proceedings the plaintiff Mrs Lina Youkhana sued the defendants Cesare Di Veroli, Lily Di Veroli, Alex Di Veroli, and Esther Lynette Di Veroli claiming damages for personal injuries which she alleged she had sustained as a result of slipping on a step forming part of stairs in a building at 18-20 Victoria Street Erskineville. It was not disputed at the hearing that the four defendants who I have named were the owners of the premises 18-20 Victoria Street Erskineville and, although they had leased parts of the building to tenants, they had not leased and were to be regarded as the occupiers of the staircase in the building. A fifth defendant, a company named Limited Addition Holdings Pty Limited ("Limited Addition") was the tenant of a part of the first floor of the building. Limited Addition was wound up and took no part in the proceedings. The proceedings were commenced in the District Court but were later transferred to the Supreme Court. At the hearing before me there were a number of strongly contested issues both as to liability and damages. 2 The evidence at the hearing consisted of two evidentiary statements by the plaintiff, oral evidence by the plaintiff, evidentiary statements by the plaintiff's husband and the plaintiff's parents, a statement by a woman named Donna Phillips, four reports by an expert witness Mr Burn retained on behalf of the plaintiff, two reports by an expert witness Dr Cooke retained on behalf of the defendants, oral evidence by Mr Burn and Dr Cooke which was given concurrently, a large number of medical reports, oral evidence given concurrently by three neurologists Dr Watson, Dr Allsop and Dr Matheson, oral evidence given individually by a surgeon Dr Ellis, oral evidence given individually by a psychiatrist Dr Robertson and a large number of documents having some relevance to some head of damages claimed by the plaintiff. 3 The statement of claim filed in the District Court was a fairly brief document. In the early paragraphs of the statement of claim it was alleged that the first four defendants were the occupiers of the premises and in pars 4 and 5 it was alleged that on 24 February 2003 the plaintiff went to the premises under a business arrangement with Limited Addition, the plaintiff not being an employee of Limited Addition. As I have already noted, it was not disputed at the hearing that the four defendants were the occupiers of the stairs and what was alleged by the plaintiff in pars 4 and 5 of the statement of claim was also not disputed. The statement of claim continued:- "6. There was on the said premises a set of stairs leading from the ground floor to the first floor. 7. The said stairs were old. 8. The said stairs were rickety. 9. The said stairs were too narrow as to the treads thereof so as to safely accommodate an adult human foot. 10. The said stairs were worn and slippery. 11. The said stairs were not fitted with any anti-slip nosings or abrasive strips or similar. 12. As the plaintiff attempted to descend the said stairs she slipped and thereupon fell sustaining to herself injury, disability, loss and damage. 13. In the circumstances the defendants and each of them were under a duty of care to the plaintiff and were in breach thereof and were negligent." 4 In their defences the four defendants admitted pars 6 and 7 of the statement of claim, denied pars 8, 9 and 10, admitted par 11 but said that the stairs were not slippery even without such non-slip strips, did not admit par 12 and denied par 13. 5 The particulars of negligence provided in the statement of claim were: "(a) Failing to take any or any adequate precautions for the plaintiff's safety (b) Putting the plaintiff in a position of peril in the circumstances (c) Failing to provide the plaintiff with proper and safe stairs on which to walk. (d) Providing the plaintiff with stairs the treads of which were too narrow to safely accommodate the human foot (e) Failing to equip the stairs with non-slip strips or nosings (f) Providing an inadequate handrail (g) Failing to provide a round handrail which could be safely gripped by the plaintiff particularly if she slipped (h) Providing a handrail which was too short (i) Providing a handrail which was square and difficult to grip (j) Failing to warn or adequately warn the plaintiff that the stairs were slippery and dangerous (k) Providing stairs which were rickety and moved under foot (l) The plaintiff relies on the fact that after the fall non-slip strips were applied to the stairs as an admission of negligence (m) Failing to maintain or adequately maintain the said stairs (n) Allowing the said stairs to become smooth, worn and dangerous" 6 I make the following observations about the particulars of negligence. 7 Particulars (a), (b) and (c) are not really particulars at all. Particular (d) is a repetition of par 9 of the statement of claim. Particular (e) is a repetition of par 11 of the statement of claim. Particulars (f) - (i) relate to the handrail for persons using the stairs and amount to allegations that the handrail was too short (that is, not high enough) and was square, rather than round. Particular (j) alleges a failure to warn; this particular was not pressed at the hearing. Particular (k) is in part a repetition of par 8 of the statement of claim. Particular (l) relies on the subsequent taking of action, which counsel for the defendants contended could not be relied on by the plaintiff by reason of s 5C(c) of the Civil Liability Act. Particular (m) is not really a particular. Particular (n) alleges that the stairs had been allowed to become smooth, worn and dangerous. 8 The statement of claim continued with a list of particulars of injuries which the plaintiff alleged she had suffered. I will be referring to these matters later in the judgment. 9 The only person who gave evidence at the hearing about the plaintiff slipping was the plaintiff herself. In pars 32-41 of her evidentiary statement the plaintiff said:- "32. The circumstances of my accident were that on 24 February 2003 I went to the Limited Addition premises which was located on the first floor of premises 18-20 Victoria Street, Erskineville. 33. It was the first time I had been to these premises. I was going to do some exchanges for some of my customers. Limited Addition, to my understanding, had only been in these premises for a short time." In par 34 the plaintiff said that she was working for Limited Addition on a contract basis. "35. I went into the building and walked up the stairs to the first floor. On my way up the wooden stairs I noticed that the stairs were very steep and that the stair treads where I put my feet were very narrow. I have fairly large feet. I take a size 9 or 9 ½ shoe." In pars 36 and 37 the plaintiff said that she was shown around the Limited Addition premises and then decided to leave. "38. The stairs were obviously old. I noticed that when I went up them they creaked under my feet. While I was upstairs one of the Limited Addition workers spoke to me about them and so I was being very careful when I descended. 39. The stairs had a handrail on each side. I was holding on to the railing on the right hand side and I was walking down the stairs carefully. 40. After I had gone down a couple of stairs I felt my foot slip on the front of the step and I fell. I can remember slipping and starting to fall. Even though my hand was gripping the rail I was unable to save myself. The next thing I remember was right down the bottom of the first set of stairs and on the landing. 41. In the fall I hurt my tailbone, my head, my low back and my neck was a bit sore. I also had pain to my right lower arm. I must have banged it on the way down." 10 In pars 42-46 of her statement the plaintiff said inter alia that she returned to the building a couple of weeks afterwards. She noticed that, since her fall, some abrasive strips had been put onto the stair treads near the leading edges and that the leading edge of each step had been painted white. 11 Some months afterwards (in August or September 2003) the plaintiff returned to the premises with Mr Burn and a representative of the solicitor then acting for her. On this occasion she observed that more strips had been placed on the stairs. Mr Burn took some photographs, including a photograph of the plaintiff's foot on one of the stair treads, showing the front of the shoe she was wearing poking over the edge of the step. The plaintiff was not wearing the same shoes on this occasion as she had been wearing on the day of the accident. 12 In oral evidence in chief the plaintiff said that she had slipped on a step in the top set of stairs before an intermediate landing. She said that at some time after the accident (apparently on a later visit to the premises with Mr Burn in September 2008) she had observed that "they had extended the tread on the steps so much (by pieces of timber and aluminium edge strips) that you can actually put a finger underneath the aluminium casing so it actually extended the tread of the step quite a fair bit". 13 In cross-examination the plaintiff said that on 24 February she could see that the stairs looked old and that the stairs were well lit. The following question and answer occurred in cross-examination:- "Q. You have said to some of the doctors you have seen that you don't have any recollection of the fall other than walking down two or three steps and then ending up on the landing, is that right? A. Correct." 14 The plaintiff said in cross-examination that she fell on the third step in the top section of the stairs and slid down about three steps onto a landing. 15 The only other lay evidence about the stairs in the premises was in a statement dated 17 November 2006 by Donna Lillian Phillips, which was tendered on behalf of the plaintiff and not objected to. Ms Phillips did not give any oral evidence. 16 In her statement Ms Phillips said that she was aware that a female had fallen down stairs at 18-20 Victoria Street Erskineville in February 2003. It was common ground at the hearing that the female referred to by Ms Phillips was the plaintiff. 17 Ms Phillips said in her statement that she had been employed on a casual basis by Limited Addition, attending the office on the first floor of the building three days a week. I infer from other parts of the statement that Ms Phillips had been so employed for approximately one and a half years. Paragraphs 11-19 of her statement were in the following terms:- "11. I am aware that there were a set of stairs leading from the ground floor to the first floor. 12. I am aware that premises was an old building and the stairs appeared to be the original stairs of the premises. 13. I am aware that the stairs were old. 15. I am aware that stairs were narrow and that I had to walk down them sideways because they did not accommodate the size of an adult foot. I recall this had to be done particularly when I was wearing high heels. 16. I am aware that the stairs were worn and slippery. 17. I am aware that the stairs were not fitted with anti-slip nosings or abrasive strips or similar. 18. I cannot recall if there were any handrails attached to the walls for support whilst walking up and down the stairs. 19. I am aware that the office was utilised and visited by many employees of the company and fashion consultants with independent contracts." Experts 18 I have already noted that two experts, Mr Burn for the plaintiff and Dr Cooke for the defendant, made reports which were admitted into evidence and gave oral evidence concurrently. Mr Burn and Dr Cooke jointly prepared a document containing "Agreed matters" and "Disagreed matters", which became exhibit N. With some minor exceptions, no objection was taken to the admissibility of any part of the reports of either expert. 19 Mr Burn's first report was dated 12 September 2003. He had inspected the premises with the plaintiff at some time between receiving instructions on 1 August 2003 and the date of his report. 20 In part 1 of his report Mr Burn set out the facts he had been asked to assume about the plaintiff's visit and fall on 24 February 2003, which were as follows:- "a. On 24 February 203 Ms Youkhana attended the offices of Limited Addition Pty Ltd located on the first level of 18-20 Victoria Street, Erskineville. b. Ms Youkhana descended the steps leading from the first level to the ground level using the street side handrail as she descended. c. At the third step from the top her foot slid forward resulting in Ms Youkhana falling coming to rest on the landing, thereby sustaining injury." 21 In part 2 of his report Mr Burn stated that the premises were an older style factory building with a staircase from a ground level leading to businesses located on the first level. 22 In part 3 of his report Mr Burn stated:- "In ascending order, the flight of stairs comprise of 5 steps, landing, 15 steps, landing and 6 steps at the top. I am instructed that Ms Youkhana slipped and fell on the third step from the top." 23 Mr Burn noted information he had received that the building had been constructed in the 1920s and that the stairs were basically as originally constructed. 24 Mr Burn continued:- "The steps are well worn, the riser face showing evidence of significant wear from being regularly struck by the toes of people walking up the stairs. Measurements of the upper step section are as follows: STEP RISER GOING G (mm) (mm) 1 185 Landing 2 180 239 3 180 242 4 179 246 5 178 234 6 180 237 Width between handrails 950 mm Width between walls 1195 mm Handrail height above nosing street side 810 mm top step 910 bottom step Handrail height above nosing other side 840 mm top step 815 bottom step Handrail construction – timber size w x d 32 x 174 In certain parts, when the foot is placed on the step the tread was noted to move under foot creating a destabilising effect. Non-slip tape had been recently installed on the steps prior to the view. It will be noted some steps had two tapes whilst others only had one. The nosings show evidence of wear and rounding. The handrails, whilst provided on both sides of the stairs, stop at each landing, presumably due to door on one or both sides of the landings. Instruction received concerning the state of the stairs at the time of the incident was: · The non-slip tapes were not installed · The white lines on the nosings visible have been applied since. In relation to the width of the stair tread it was observed whilst on site the tread width was less than the length of Ms Youkhana's foot. Normally a person descending stairs would not place their foot hard up against the back of the step as shown in figure 4 (the photograph of the plaintiff's foot taken by Mr Burn) but far enough forward to clear the nosing as they stepped down." 25 The word "width", which was often used at the hearing, is ambiguous but when used at the hearing usually referred to the dimension of a step in the same direction as a person using the step is walking. The words "depth" and "length" were also used to describe the same dimension. 26 Figure 4 in Mr Burn's report is a photograph of the plaintiff's foot wearing a shoe, pointing straight forward, that is at right angles to the edge of the step. In the photograph the heel of the plaintiff's shoe is up against the riser of the step behind her. The toe of her shoe projects over the edge of the step but only slightly. 27 In part 4 of his report Mr Burn set out certain provisions of ordinance 71 pursuant to the Local Government Act 1919, including clauses 61(c), 61(d) and 61(e). These clauses were in the following terms:- "61(c) The minimum unobstructed width of an interior stairway serving as a means of exit for flats containing not more than 60 habitable rooms shall be not less than 3 feet 6 inches (1067mm) and shall be increased 3 inches (76mm) for every additional 10 habitable rooms or fractions thereof. TREADS - NON SKID MATERIAL 61(d) Treads of stairs and the graded surfaces of the stairway shall be effectively treated with non-skid materials. TREADS AND RISERS - WIDTH AND HEIGHT 61(e) Treads and risers of interior stairs shall be of a uniform width and height throughout but the risers shall not exceed 7.25 inches (184mm) in height and tread, exclusive of nosing, shall be not less than 9.5 inches (241mm) in width." 28 Mr Burn then said:- "The staircase on which Ms Youkhana fell did not comply with the Ordinance in that: a. Its width was less than 1067 mm b. The treads of the stairs were not effectively treated with non-skid materials at the time of the incident c. A number of the treads were less than 241 mm in width" 29 It is clear that Mr Burn's first report was prepared by him on the basis that Ordinance 71 applied to the staircase at the premises. However, it later became an agreed matter between Mr Burn and Dr Cooke (agreed matter 6) that no provision of Ordinance 71 applied to internal stairs in a commercial building, such as the stairs in the present case. 30 Notwithstanding that no provision of Ordinance 71 applied to the stairs on which the plaintiff slipped, the hearing was conducted by counsel for both parties on the footing that there was some utility in considering whether the stairs would have complied with the Ordinance, had the Ordinance applied. 31 As to respect (a) in which Mr Burn stated that the staircase did not comply with the Ordinance, it was irrelevant to the plaintiff's slipping that the width of the staircase, that is the cross-dimension of the staircase, was less than 1067 metres. As to respect (c), while some of the treads as measured by Mr Burn were less than 241 mm in "width", the deficiency was very slight and the tread on which the plaintiff slipped, whether it was step 3 or step 4 in Mr Burn's table, was not less than 241 mm in width. 32 In his report Mr Burn then discussed the handrails and said that a circular shaped handrail is preferable "as it gives a person something to grip should they lose their footing and stumble while using the stairs. The rectangular section used is much more difficult to grip under emergency events (eg slipping and falling)". 33 In part 5 of his report Mr Burn said:- "This is the main access route from the main entrance of the building to the first level where the business is conducted. This access route was comprised of worn and smooth steps with no anti-slip measures taken and in these circumstances, I am of the opinion that an accident of the type under review was clearly foreseeable." 34 In part 6 of his report Mr Burn said:- "This accident could have been prevented by: a. Resurfacing the steps in a material containing anti-slip qualities such as carborundum or anti-slip tiles b. Placing adequate anti-slip treatment on the nosing of each step, as has occurred since the accident. c. Using an alternative shaped handrail section (e.g. circular) that was easier to grip than the existing rectangular section." 35 In part 7 of his report Mr Burn said that the "primary cause of the accident was the failure to provide a main access route with a staircase that complied with provisions of the relevant Ordinance". 36 Dr Cooke's first report was dated 7 June 2006. He had inspected the premises on 23 May 2006. 37 In par 10 of his report Dr Cooke summarised the instructions he had received about background facts, which appear to me to be in accordance with the evidence in the case, although in some respects going into greater detail. In sub-par (x) Dr Cooke said:- "Staircase is thought to be approximately 50 years old and consists of 26 steps (rises) and 2 landings. The staircase is positioned in an enclosed corridor. A handrail is located on each side of the staircase." 38 A large part of Dr Cooke's report was under a heading "Evaluation". In par 16 Dr Cooke said that "the timber treads have a polyurethane or similar coating, which has worn away in heavily trafficked areas". 39 In par 18 of his report Dr Cooke said, it being alleged (on behalf of the plaintiff) that the stairs were "worn and slippery", he had assumed that the treads were worn at the time of the accident, approximately to the extent shown in a photograph he took in May 2006, and that the worn surface extended to the nosing of the tread. However, he had also measured the slip-resistance of some of the timber surfaces where the coating was not significantly worn. 40 In par 20 and 21 of his report Dr Cooke noted that nothing in Ordinance 71 related to the design of the staircase. He added, "however, good practice requires stair nosings (or the entire tread surface) to be reasonably slip resistant". 41 Using the test method set out in each of the Australian Standard/New Zealand Standard 3661.1.1993 and Australian Standard/New Zealand Standard 4663:2002, Dr Cooke measured the dynamic coefficient of friction of typical worn surfaces and obtained an average reading of 0.5 (rounded down) from four readings of 0.48, 0.49, 0.55 and 0.51 and he also measured the dynamic coefficient of friction of less worn surfaces on the landings and obtained an average reading of 0.45 (rounded) from five readings of 0.42, 0.44, 0.42, 0.47 and 0.52. 42 Under Australian Standard/New Zealand Standard 3661.1.1993 an average dynamic coefficient of friction of at least 0.4 indicates that the surface is "slip resistant". Under Australian Standard/New Zealand Standard 4663:2002 an average dynamic coefficient of friction of at least 0.4 indicates that the contribution of the floor surface to the risk of slipping when dry is "moderate to very low". 43 Under Australian Standard/New Zealand Standard 4663:2004 an average dynamic coefficient of friction of at least 0.4 indicates that the notional contribution of the floor surface to the risk of slipping when dry is "moderate to very low". The word "notional" highlights the need to consider all potential contributing factors to a slip incident. 44 The current Building Code of Australia cl D2.13(b)(v) relating to stairways provides that a stairway satisfies the requirement that a stairway be suitable to provide safe passage, if it has treads which have a non-slip finish or a suitable non-slip strip near the edge of the nosings. In par 28 of his report Dr Cooke said that "my tests show that the timber tread surfaces at the time of the plaintiff's accident (before the metal nosings were fitted) had adequate slip resistance and complied with the current Building Code of Australia cl D2.13(b)(v). 45 Dr Cooke measured the steps in the top flight and found the top "riser" to be 190 mm and the remaining risers to be 180 mm and the top "going" to be 250 mm and the other goings to be 240 mm (ignoring the metal nosings added after the date of the accident). In the evidence he gave at the hearing, Dr Cooke described the "going" of a step as being the useable part of the tread. Dr Cooke observed that "under the current Building Code of Australia the maximum riser for a public stair (in a commercial building) or private stair (in a house) is 190 mm…the minimum going for a public stair is 250 mm and the minimum going for a private stair (in a house) is 240 mm". 46 Dr Cooke stated his conclusions as follows:- "36. The stair dimensions comply with the current BCA requirements for stairs in domestic buildings, being the minimum of 240 mm specified in Table D2.13. The going is 10 mm short of the minimum specified for stairs in public buildings in Table D2.13 and 10 mm short for a stair with riser of 180 mm under AS 1657-1992 Figure 4.3 (see Appendix K). 37. There is no requirement for stair treads to be large enough to take the entire length of an adult foot without any overhang. In normal descent, the toe of the shoe naturally overhangs the nosing of the tread as the ball of the foot is placed on or near the nosing, irrespective of the size of the stair tread. 38. No building regulations applied to the design of the stair at the assumed date of construction (about 50 years ago). The stair geometry does not pose a hazard for stair users exercising reasonable care for their own safety. 39. The current BCA cl.D2.13(b)(v) requires stair treads to have a non-slip finish throughout or a suitable non-skid strip near the edge of the nosings. My tests show that the timber tread surfaces at the time of the plaintiffs accident (before the metal nosings were fitted) had adequate slip resistance and complied with the current BCA cl. D2.13(b)(v). Anti-slip nosings are not required under the current BCA cl. D2.13(b)(v) as the timber tread surface (both worn and less worn) is slip resistant in itself. 40. The stair has a handrail on both sides. Under the current BCA cl. D2.17(a)(i) and (v), one handrail would be required at a minimum height of 865 mm. The handrail on the left hand side in the direction of descent complies with the current BCA. The handrail on the right hand side is about 790 mm high. This is 10 mm lower than the minimum of 800 mm for a handrail specified in AS 1657-1992 cl. 4.6.2, but it is able to provide a hand hold for stair users. No handrail would be required on the right hand side of the stair under the current BCA cl. D2.17 as the stair has a handrail on the left hand side. 41. The BCA does not specify the shape of a handrail. AS 1657 specifies handrails to be a pipe of not less than 30 mm outside diameter or a timber handrail not less than 70 mm x 45 mm. The handrails provided are rectangular in cross section. This is not the optimum shape for a power grip (which has been shown to be about 45 mm in diameter; see page 1005 of article by Pauls reproduced in Appendix L), but is of a size and shape that can be grasped and is able to provide support for a stair user. 42. Given the age of the building, the time of construction (about 50 years ago), the fact that no building regulations apply and the fact that no Australian standard is of general application to staircase design, the stair provides suitable access. It complies with the current BCA requirements for stairs in domestic buildings. The stair is not "rickety" as alleged. 43. There is no relevant aspect of the staircase that would not be other than obvious to a reasonable user of the staircase." 47 Mr Burn was asked to comment on Dr Cooke's report of 7 June 2006. In his report of 8 August 2006 Mr Burn made inter alia the following comments. 48 Mr Burn pointed out that Dr Cooke had conducted his tests more than three years after the slipping incident. Dr Cooke had conducted his tests to determine the coefficient of friction on areas of the step treads between the aluminium nosing and the step riser and not on the front part of the step tread on which the ball of a person's foot would be placed while the person was descending the stairs and which, by the time Dr Cooke had performed his tests, had become concealed under the aluminium nosings. Mr Burn said "this area (on which the tests were performed) receives less wear than the nose area of the steps". 49 Mr Burn made a criticism of the method used by Dr Cooke in conducting his tests. Mr Burn said:- "It is noted the standards referenced require dry coefficient of friction tests to be conducted over a length of 800 mm. Where this is not possible the combined test length is required to be 800 mm. The copies of test printouts mostly appear to cover test runs of 200 mm length. On this basis they equate to a single test run each." 50 Mr Burn concluded:- "The tests undertaken and reported by Dr Cooke indicate the back half of the stair treads has adequate friction to permit a person under normal circumstances to ascend/ descend the stairs. This area however is behind the area where a person descending the stairs would normally tread. The area trodden on at the time of the alleged incident was under the aluminium stair nosings on the day of Dr Cooke's tests and therefore could not be evaluated. The tests undertaken on the mid/back half of the stair treads do not replicate the surface conditions of the nosings at the time of the alleged incident." 51 Dr Cooke was asked to provide a supplementary report, having regard to Mr Burn's report of 8 August 2006. 52 In par 8 of his supplementary report Dr Cooke said in part:- "I tested the timber surfaces in various locations to obtain readings for worn and less worn timber surfaces. It is not possible to test the nosing of the tread on which the plaintiff allegedly slipped as it has been covered by a metal nosing of the type described in Tax Invoice No 89354 (see Appendix A). As the nosings were supplied in or about March 2006, even if the nosing were now removed from the tread on which the plaintiff allegedly slipped for the purpose of testing the timber surface, the timber surface underneath would not be precisely the same as it was at the time of the accident…" 53 In his supplementary report Dr Cooke defended the way in which he had conducted his tests. He said in par 10:- "Where space permitted, I used a continuous test path of 800 mm (the last print out in Appendix H to my first report). The treads are too short to conduct a test over a continuous path of 800 mm. In those cases I used four test paths of 200 mm on each type of surface being tested to give a cumulative total of 800 mm, as shown in the first four print outs in Appendix H to my first report and in Appendix I to my first report. The 200 mm test runs do not equate to a single test run each. The results of the four test runs of 200 mm each on each test surface have been averaged to give a result for a cumulative test path of 800 mm, in accordance with the standards." 54 In par 11 of his report Dr Cooke said:- "I have tested some thousands of pedestrian surfaces, including many timber surfaces. With extremely rare exceptions, dry pedestrian surfaces have a dynamic coefficient of friction of at least 0.4. I have never found a timber surface with the type of finish used at the premises to have a dynamic coefficient of friction of less than 0.4." 55 In par 14 of his supplementary report Dr Cooke said:- "Mr Burn asserts on page 4 that I tested the back half of the treads, which is correct. However, the tests are not invalid as I have assumed that the front part of the treads would have been worn and I have tested worn surfaces." 56 Dr Cooke annexed to his second report an invoice to the defendants dated 22 March 2006 for the costs of providing the aluminium nosings on the steps. 57 In a further report of 5 March 2007 Mr Burn commented on Dr Cooke's supplementary report. 58 In this further report Mr Burn said:- "Dr Cooke proposes the coefficient of friction for timber surfaces are rarely less than 0.4. Testing of timber surfaces I have reported on has shown timber coefficient of friction to be as low as 0.20 and average coefficient of friction in the range of 0.41 to 0.45. Presumably Dr Cooke's statement refers to the average coefficient of friction, not the minimum coefficient of friction measured." 59 Mr Burn concluded that "the fitting of the nosing to the stairs at 18-20 Victoria Street Erskineville in April 2006 has made the stairs safer for pedestrian use by reducing the likelihood a person's foot will slip off the worn leading edge". 60 Mr Burn prepared a further report dated 10 September 2008. He had again visited the premises with the plaintiff on 3 September 2008. 61 In this further report Mr Burn said:- "I noted that since my previous inspection, the stairs have been modified by the addition of a piece of timber to lengthen the tread of the steps except for the top landing. This modification can be seen in figures 1 and 2." 62 It seems clear that the addition of the pieces of timber and the aluminium strips has lengthened the tread of the steps but it is difficult to reconcile Mr Burn's statement that the additions have lengthened the goings (as distinct from the treads), with measurements of the goings he made in 2008. 63 In his report Mr Burn recorded measurements he had made of the handrails and of the gradients of the steps. 64 On this visit Mr Burn carried out his own tests to determine the coefficient of friction of the steps when dry and set out the results of his tests. On some of the tests conducted on landings he obtained a figure of less than 0.4. However, on tests performed on the five steps in the top section of the stairs only one result (on the fourth step) was less than 0.4. On the third step the results obtained by Mr Burn were 0.42 and 0.41. 65 Mr Burn concluded:- "The stair treads have worn between the added stair nosing material and the rises improving tread coefficient of friction by the removal of the original surface treatment. In their current state the stair treads would be classified as " moderate to low risk ". In areas where the original surface finish still remained the surface dry coefficient of friction is significantly lower then on the stair treads. The surfaces still finished with the original finish would be classified as " high to very high " risk." 66 As I have already noted, Mr Burn and Dr Cooke conferred before giving oral evidence and produced a joint document, which was in the following terms:- "AGREED MATTERS 1. The premises were constructed in the 1920s. 2. Ordinance 71 applied. 3. The stairs may have been re-constructed about 50 years ago. 4. If so Ordinance 71 applied. 5. The building is and was commercial. 6. No provision of Ordinance 71 applied to internal stairs in a commercial building. 7. Good practice required the tread surface and nosing of each stair to be reasonably slip resistant. 8. Prior to the plaintiff's fall the stairs had been coated in a proprietary polyurethane or similar finish. Portions of that finish were present during expert inspections. 9. The non-slip strips of each of the treads were installed after the plaintiff's fall. 10. The aluminium nosing strips were installed by the defendants in March 2006. 11. The BCA and Australian Standards are not retrospective and did not apply. 12. No coefficient of friction testing has been possible on the third stair under the new nosing strip. 13. The stair treads with new nosings are likely to pose a moderate to very low risk of slipping incidents occurring. 14. It is acceptable for coefficient of friction testing to adopt Table 2 of AS/NZS 4663.04. DISAGREED MATTERS 1. That wear on the nosing of the tread would contribute to slipping. 2. That testing behind the new nosing strips is a fair indication of what is underneath the strips. 3. That the handrail is adequate. 4. That wooden packers have been installed on the risers next to the nosings so as to accommodate the new aluminium nosing strips. 5. That the new nosing strips make each individual tread approximately 28-30 mm deeper. 6. That wooden surface stair treads are always moderate to low risk surfaces. 7. That the worn sections were always less slippery than the less worn sections of the treads. 8. That the polyurethane or similar coating was in itself slippery." 67 In the course of the hearing disagreed matter 4 became an agreed matter. In the course of the hearing Dr Cooke said that he agreed with disagreed matter 5, provided that the word "tread" was read literally as meaning "tread" and not as meaning "going". As to the remaining disagreed matters, the expert affirming each matter was:- 1. Mr Burn 2. Dr Cooke 3. Dr Cooke 6. Dr Cooke 7. Dr Cooke 8. Mr Burn Experts' oral evidence 68 As I have already noted, Mr Burn and Dr Cooke gave evidence concurrently. Most of the questions were directed by counsel for the plaintiff to Dr Cooke. Dr Cooke's evidence 69 The polyurethane coating would have been applied for decorative, cosmetic purposes. As the coating wore off, the timber would be revealed and would be less slippery than the original surface (that is the coefficient of friction would be increased). No information has been supplied to Dr Cooke about when the coating was applied or how frequently (if at all) it had been renewed. Dr Cooke accepted that there would have been additional wear between the time of Mr Burn's visit in 2003 and his own visit in 2006. The more traffic there was on the stairs the more the coating would be worn off and the more slip resistant the underlying timber would be. 70 On his visit Dr Cooke had walked up and down the stairs in his size 10 ½ men's shoes. He had not tried to lose his footing. He found that there was no need for him to walk sideways in order to have the ball of his foot placed on the stairs. 71 Dr Cooke agreed that "as someone descends a set of steps they descend placing the ball of their foot on the tread surface". 72 Dr Cooke distinguished between the "tread" and the "going" of a step in a set of stairs. The going is the useable part of the tread. Dr Cooke said:- "The going is measured between the faces of consecutive nosings, which often are sloping or overlapping the adjoining nosings, so to the extent there's an overlap or a slope that part of the tread is not useable, so the going is the useable part as measured between the consecutive nosings." 73 The addition of the pieces of timber and the aluminium strips, while it had increased the treads of the steps, had not increased the goings of the steps. 74 With regard to the handrail, Dr Cooke said that in his opinion the handrail had been adequate for the purpose of allowing "the user of the stairs to steady himself or herself with minor misstepping incidents". Dr Cooke accepted that "the optimum shape for a power grip is 45 mm diameter railing, so that is undeniable that that type of railing provides a better power grip than rectangular railing". 75 It would not be natural for a user of the stairs to move the heel of the user's shoe back against the riser as the user descended, although "it could be done very deliberately and carefully to avoid the heel striking the upper nosing while doing it". 76 Dr Cooke was unable to explain why there was some differences between the measurements of the steps made by himself and the measurements made by Mr Burn. Dr Cooke had used a set square in making his measurements. He accepted that it would have been easier to Mr Burn to make measurements in 2003, before the aluminium strips were added to the steps. 77 Dr Cooke gave evidence about the nosings of the steps. He disagreed that wear on the nosing of the treads would contribute to slipping. As the surface wore at the nosing, it did not become slippery. The following question and answer occurred in the cross-examination:- "LIDDEN: But it is fundamental that if one wears away the corner, that is the more or less right angled corner of the nosing, there becomes less horizontal surface on the tread to accommodate the human foot. WITNESS COOKE: If there is a significant wear, yes it would have to be a significant amount of wear for that to be a factor." 78 All timber treads are already slightly rounded. It is good practice to have rounding on internal timber steps, because otherwise the sharp end (of the tread) would become splintered and damaged from normal use. 79 Later in his evidence Dr Cooke said:- "It would have to be an extreme amount of wear for that phenomenon to occur. I find it very hard to believe that on this stair that would have occurred." 80 When shown photographs taken by the plaintiff two weeks after the incident (after the leading edges of the steps had been painted white), Dr Cooke said:- "I think if I could start. The white paint actually is helpful because to me it shows that there's been no significant wear or rounding as a result of wear." 81 Dr Cooke said in his evidence:- "I tested two types of surfaces bearing in mind that the surfaces were worn. I tested the worn area. I then, because of the comparison, I tested a less worn area where there was a significantly evident amount of polyurethane. Now both those results showed, they produced readings above point 4. Now, there was nothing in the readings that made me think if there had been more polyurethane, the surface would have had a reading of less than .4. I accept in that lapse of time, assuming there was no extra coating, then at least certainly in the parts people tread most frequently there would have been more wear than there was at the time of the accident." 82 Dr Cooke said that, because the wear on a nosing is higher than elsewhere and as a worn surface is less slippery than an unworn surface, nothing would have been achieved by testing a nosing itself, if that could have been done, because the resulting coefficient of friction would have been almost certainly higher than the results Dr Cooke obtained on the parts of the tread he could test. Mr Burn's evidence 83 Mr Burn had not said anything in his first report about having observed any recent application of polyurethane coating and said that he had not noticed if any coating had recently been applied. 84 Mr Burn agreed that it is normal for people to walk down stairs with part of their foot extending over the front edge of the step, with the ball of the foot being just behind it. 85 Mr Burn had seen rectangular handrails but round handrails were more common. 86 Mr Burn considered that the nosing of the step could have contributed to slipping by becoming rounded or eroded by the wearing away of the timber and because certain types of timber become smooth and polished from wear under use. 87 The following questions and answers occurred in Mr Burn's evidence:- "SEXTON: Now as I understand it the proposition about the polishing of the wood depends on the type of the timber? WITNESS BURN: Yes. SEXTON: And in order to demonstrate the relevance of that to this particular staircase, you would need to identify the timber and to test it to see whether some sort of wearing of it would cause it to polish in that way? WITNESS BURN: Yes. SEXTON: And that hasn't been done? WITNESS BURN: No." 88 The following question and answer occurred in Mr Burn's evidence:- "SEXTON: And at the time of your first visit apart from the fact that you were instructed that the plaintiff had fallen about six and a half months earlier, you had no other evidence to demonstrate that the stairs did not have adequate slip resistance even without the measures you referred to in paragraphs a and b (in part 6 of his reports) did you? WITNESS BURN: No." The submissions of the parties 89 The principal submissions made on behalf of the parties can be briefly summarised as follows. Counsel for the plaintiff's submissions 90 The plaintiff's account in her evidentiary statement of how the fall occurred, on which there was little cross-examination, should be accepted. 91 Dr Cooke's evidence about his testing so as to determine coefficients of friction should be rejected. Dr Cooke had been unable to test the coefficient of friction of the nosings of the steps, which had been covered by the aluminium strips. Dr Cooke carried out his tests more than three years after the plaintiff's fall and there was no evidence that the stairs were in the same condition as they had been at the time of the fall. On the contrary, there was some evidence suggesting that there had been changes in the condition of the steps. When Mr Burn compared photographs he had taken some months after the incident with photographs taken by the plaintiff two weeks after the incident, the surface of the stairs as shown in the photographs appeared to Mr Burn to be different. Counsel also referred to a difference of 15 mm in measurements made by Dr Cooke and by Mr Burn in 2008 of one going, which it was submitted could only be explained on the basis that there had been some change in the stairs. 92 The stair treads were too short. Counsel referred to the evidence of the plaintiff and Ms Phillips and to Mr Burn's evidence about the wear to the risers. Dr Cooke's evidence about his being able to walk up and down the stairs without difficulty should be rejected. The defendants (or someone else) had lengthened the tread by adding the pieces of timber and the aluminium strips, because it was realised that the stair treads were too short. 93 The leading edge or nosing of the steps (and particularly of the step on which the plaintiff slipped) was slippery. 94 The handrail should have been circular and not rectangular. 95 The subsequent actions of the defendants (or someone else) in affixing the non-slip strips and in installing the pieces of timber and the aluminium strips could be relied on by the plaintiff in establishing a case in negligence, particularly because of the timing of the taking of the actions and the obvious purpose of the actions. 96 In the absence of evidence from or on behalf of the defendants on a number of matters, inferences adverse to the defendants could and should be drawn on those matters, including whether there had been previous accidents on the stairs and previous complaints about the stairs and whether a fresh polyurethane coating had been applied to the stairs from time to time. 97 Counsel for the plaintiff summarised the plaintiff's case as follows:- "The most minor one is the creaking. It might go somewhere - its importance is uncertain but I'm not abandoning it as providing some movement of the stair treads but the important ones are the fact that the treads were too short - that's the first one - that the nosings of those treads were slippery, a combination of those two things meant that slipping or stumbling incidents were highly likely and in those circumstances the railing - the handrail, which gave less than optimal grip was not good enough." Counsel for the defendant 98 Counsel referred to principles of law about the extent of the obligation to take care required of an occupier of premises. The mere occurrence of a fall on stairs does not give rise to an inference that the stairs were defective. 99 In the present case the fall had occurred on one of a set of five or six steps between landings. It was not a case of a single set of long, steep stairs. All features of the stairs were obvious and the stairs, at the time the plaintiff was using them, were well lit. 100 The plaintiff's evidence about how the fall had occurred was non-specific as to how she had slipped. 101 The plaintiff had not established that the stair treads were too short or that the nosings of the steps had been slippery or that the handrail was inadequate. 102 On the basis of Dr Cooke's evidence it should be found that the nosings of the steps were not slippery. 103 As regard the length of the stair treads, the step on which the plaintiff slipped would have met the requirements of Ordinance 71, if the Ordinance had applied. There was no evidence that the step on which the plaintiff slipped failed to comply with any applicable standard. It was clear from an inspection of the photograph taken by Mr Burn in 2003 that the plaintiff could walk down the steps, without stepping sideways and without the ball of her foot being over the front edge of the steps. 104 The only solution to any problem about short treads, if it existed, would have involved re-building the entire set of steps. Dr Cooke's evidence should be accepted that the installing of the pieces of timber and the aluminium strips, while it had lengthened the treads, had not increased the goings, that is the useable parts of the treads for a person walking down the stairs. 105 It was necessary for the plaintiff to establish that any particular defect was an operative cause of her fall. The plaintiff's account of her fall did not establish that any shortness of the treads was an operative cause of the fall. 106 In his first report Mr Burn said that "in certain parts" when the foot was placed on a step the tread was noted to move. However, without identifying the "certain parts" the evidence went nowhere. 107 Donna Phillips' evidence was of little significance. The question was whether the plaintiff had established that the stairs did not meet accepted standards, not whether one person had a non-specific and undefined opinion at some point in time. In her statement Donna Phillips had associated "worn" and "slippery", yet the experts were in agreement that the more worn the timber was, the less slippery it was (subject to Mr Burn's evidence that certain, unspecified timbers could become polished and smooth with wear). 108 The plaintiff was prevented by s 5C(c) of the Civil Liability Act from relying on the subsequent taking of actions that might have avoided a risk of harm. 109 There was no evidence of any previous fall on the stairs or complaint about the stairs. The onus was on the plaintiff to prove any previous fall or any previous complaint. It would not be permissible for the court to draw an inference that there had been previous falls or previous complaints, because the defendants had not given evidence on these matters. The degree of wear observed by both Dr Cooke and Mr Burn (including Mr Burn on his first visit) suggested that the stairs had been successfully used by a large number of persons. From Donna Phillips' statement it could be inferred that she had used the stairs on at least a couple of hundred occasions. She did not say in her statement that she had ever slipped, that she was aware of any one else falling or that she was aware of any complaint having been made about the stairs. 110 Generally, counsel disputed that the court could draw the inferences which counsel for the plaintiff had submitted the court should. Decision 111 It is necessary to have regard to the general principles stated in Pt 1A of the Civil Liability Act, including that a person is not negligent in failing to take precautions against a risk of harm, unless the risk was foreseeable, the risk was not insignificant and a reasonable person in the person's position would have taken those precautions (s 5B). A subsequent taking of action that would (had the action been taken earlier) have avoided a risk of harm does not of itself give rise to or affect liability and does not of itself constitute an admission of liability (s 5C(c)). 112 It is also necessary to apply authoritative statements which had been made about the extent of an occupier's liability and particularly in relation to stairs on the premises of the occupier. "…an occupier of premises is only required to take such care as is reasonable in the circumstances. The duty is not to make the premises as safe as reasonable care and skill on the part of any one can make them" ( Wilkinson v Law Courts Limited [2001] NSWCA 196 at 21 per Heydon JA). 113 In the same case Heydon JA said at 32:- "…Stairs are inherently, but obviously, dangerous. Many measures might have been taken to make the stairs as safe as human skill could possibly make them; but the duty is only to take care which is reasonable under the circumstances. Among the essential circumstances is the following fact: "persons using steps may misjudge their footing and slip or trip but this is an everyday risk which members of the public avoid by taking care for their own safety"…" 114 In the present case I find that the circumstances include that the stairs were old; that, contrary to the plaintiff's evidence (par 35 of her statement) the stairs were not "very steep"; that each part of the stairs contained only a few steps; that at the time the plaintiff was using the stairs the stairs were well lit; and that there was no feature of the design of the stairs which would not have been obvious to any user of the stairs. I will make further findings about the stairs later in the judgment. 115 At the hearing counsel for the plaintiff submitted that the plaintiff's account of how she slipped and fell, on which there had been little cross-examination, should be accepted. It is true that there was little cross-examination on the plaintiff's account. However, as was submitted by counsel for the defendant, the plaintiff's evidence about how the fall had occurred was brief and non-specific. In par 40 of her statement the plaintiff simply said that she felt her foot slip on the front of the step, she started to fall and was unable to save herself. The instructions given to Mr Burn were simply that the plaintiff had slipped and fallen. In cross-examination at the hearing the plaintiff agreed that she had told some doctors she had seen that she had no recollection of the fall, other than walking down two or three steps and then ending up on the landing. 116 In summarising the submissions of the parties I have referred to a submission, or rather a group of submissions, made by counsel for the plaintiff that, in the absence of evidence from or on behalf of the defendants on a number of matters, inferences adverse to the defendants could and should be drawn on those matters, including whether there had been previous accidents on the stairs and whether there had been previous complaints about the stairs and whether a fresh polyurethane coating had been applied to the stairs from time to time, which might have made the stairs more slippery. Counsel for the plaintiff referred to Brady v Girvan Bros Pty Ltd (1986) 7 NSWLR 241. 117 These submissions invoke principles often compendiously referred to as the rule in Jones v Dunkel (1958-59) 101 CLR 298. The rule in Jones v Dunkel is discussed in Cross on Evidence Australian edition at par 1215 and was discussed by Campbell JA in Manly Council v Byrne [2004] NSWCA 123 at pars 44-55 and in Howell v Macquarie University [2008] NSWCA 26 at pars 93-99. 118 Some principles which emerge from the discussions are that an unexplained failure by a party to call evidence, when it would have been within the power of the party to call the evidence, may lead to an inference that the uncalled evidence would not have assisted that party's case. The inference may be drawn; it does not have to be drawn. The rule permits an inference that the uncalled evidence would not have assisted the party not calling the evidence. However, the rule does not permit an inference that the uncalled evidence would in fact have been damaging to the party not calling it. If the rule applies the tribunal of fact may draw with greater confidence an inference unfavourable to the party not calling the evidence, which is open on the evidence which has actually been given. The rule cannot be applied so as to fill gaps in the evidence or to convert conjecture or suspicion into an inference. 119 In the present case there was simply no evidence actually given from which any inference could be drawn that there had been previous accidents on the stairs or that there had been previous complaints about the stairs or that there had been a fresh application of the polyurethane coating to the stairs and therefore no inference which might be drawn with greater confidence because of the absence of evidence which might have been called by the defendants. 120 Such limited evidence as was actually given would tend to suggest an absence of previous accidents. The only accident Ms Phillips referred to was the accident to the plaintiff. Ms Phillips' evidence would suggest that she herself had used the stairs at least a couple of hundred times. 121 Brady v Girvan Bros, the case relied on by counsel for the plaintiff, was a very different case from the present. In that case it was held that a customer in a large and busy shopping mall, who slipped on a substance which had been spilled or dropped on the floor in a common passageway, was entitled to recover against the occupier of the shopping mall. The Court of Appeal held that in the circumstances of the case it could be inferred that the occupier did not have a proper system for watching for and removing spillages. 122 I consider that I should proceed on the basis that there is no evidence of any previous accident involving a person slipping or falling on the stairs and that there is no evidence of any previous complaint about the stairs and that there is no evidence that there had been a recent application of the polyurethane coating to the stairs. 123 Earlier in this judgment I referred to counsel for the plaintiff's summation of the plaintiff's case, that there was movement in the stair treads, that the stair treads were too short, that the nosings of the stair treads were slippery and that the handrail was inadequate. 124 Not included in the summation were the actions taken by the defendants (or by someone), subsequent to the plaintiff's accident, in applying, soon after the accident, the non-slip strips to the treads and in applying, in 2006, the aluminium nosings and the timber packers. I have already noted that the subsequent action of applying the non-slip strips was alleged in the statement of claim to be a particular of negligence and counsel for the plaintiff in his final address did make some submissions about both of the subsequent actions. It was submitted that the subsequent actions were more strongly indicative of negligence, because of their timing (they occurred soon after the accident or, it was suggested, soon after service of the statement of claim commencing these proceedings) and because of their obvious purpose, that is to make the stairs safer. However, I consider that, as appears to have been ultimately recognised by counsel for the plaintiff, the plaintiff is barred from relying on these subsequent actions as of themselves affecting liability, by the provisions of s 5C(c) of the Civil Liability Act. 125 Of the matters mentioned by counsel for the plaintiff in his summation the first matter mentioned was movement in the stair treads. Counsel said that he was not abandoning this matter, although he described it as "the most minor" matter on which he was relying. 126 Mr Burn said in his first report that "in certain parts" of the stairs he noticed that when he placed his foot on a step, the tread moved. Mr Burn did not identify "the certain parts" of the stairs. The plaintiff said in her statement that when she walked up the stairs they creaked under her feet. The plaintiff did not say in her statement anything about there having been any movement under her feet while she was descending the stairs. 127 I do not consider that I should find that some movement of the step on which the plaintiff had placed her foot played a part in the plaintiff slipping. 128 A matter strongly relied on by counsel for the plaintiff was that the treads of the stairs were, allegedly, too short. 129 On his first visit Mr Burn measured the goings or the treads of the steps in the top section of the staircase (Mr Burn would not appear to me to have distinguished between "goings" and "treads") and in his first report Mr Burn said that the staircase did not comply with ordinance 71 in that, inter alia, a number of the treads were less than 241 mm in width (that is, in length). 130 Mr Burn was correct in supposing that ordinance 71 applied to the building but was in error in supposing that any provision of ordinance 71 applied to the stairs. If ordinance 71 had applied to the stairs, then, according to the measurements made by Mr Burn on his first visit, the treads of the steps which could have been the step on which the plaintiff slipped, were not less than 241 mm and the amounts by which any of the other steps were less than 241 mm were very slight. 131 The current Building Code of Australia does not, of course, apply to the building at 18-20 Victoria Street. However, a measurement of 240 mm for a going (which was the measurement made by Dr Cooke for all of the goings, apart from one for which there was a higher measurement) would only be 10 mm (that is 1 cm) less than the minimum required by the Code for a public stair and would not be less than the minimum required for a private stair. 132 Mr Burn remarked in his first report that the risers of the stairs showed evidence of significant wear from being regularly struck by the toes of persons walking up the stairs. However, the stairs were possibly 80 years old and at least 50 years old (see agreed matters 1 and 3) and had clearly been extensively used and I would not infer from the evidence of wear on the risers that the treads of the stairs were too short. 133 Considerable reliance was placed by counsel for the plaintiff on the photograph of the plaintiff's foot taken by Mr Burn on his first visit, showing the heel of the plaintiff's shoe up against the riser of the step behind her and the toe of her shoe projecting over the edge of the step. I do not consider that this photograph has the significance sought to be attached to it by counsel for the plaintiff. I have already quoted par 37 of Dr Cooke's first report, which I accept and which I will now repeat:- "There is no requirement for stair treads to be large enough to take the entire length of an adult foot without any overhang. In normal descent, the toe of the shoe naturally overhangs the nosing of the tread as the ball of the foot is placed on or near the nosing, irrespective of the size of the stair tread." 134 In his oral evidence Mr Burn agreed that it is normal for people to walk down stairs with part of their foot extending over the front edge of a step, with the ball of the foot being just behind it. In the photograph the plaintiff's foot projects only very slightly over the edge of the step (I accept, of course, that the plaintiff's heel is further back on the step than it normally would be). 135 Having regard to the measurements of the treads made by both Dr Cooke and Mr Burn and the evidence by both Dr Cooke and Mr Burn about how people normally walk down stairs, I do not accept Ms Phillips' assertion in her statement that because the steps were "narrow" she had to walk down the stairs sideways. The plaintiff did not suggest in her evidentiary statement that she was walking down the stairs sideways. 136 I consider that I should accept Dr Cooke's evidence that it would have required an extreme amount of wear for there to have been any significant rounding of the nosings so as to reduce the length of the treads and his evidence that an inspection by him of the photographs taken two weeks after the accident showed that there had been no significant rounding as a result of wear. 137 I also accept Dr Cooke's evidence about the distinction between "treads" and "goings", a matter about which Mr Burn sometimes seemed to be unclear, and his evidence that, while the fixing of the aluminium nosings with the pieces of timber had lengthened the treads, it had had no significant effect on the goings. 138 I turn to the question of whether the stair treads, and particularly the nosings, were slippery. 139 In his first report made after his first visit Mr Burn noted that the steps were "well worn". On his first visit Mr Burn did not make any measurements of the degree of slipperiness of otherwise of the steps. 140 On his first visit Dr Cooke did make measurements of the coefficient of friction of both worn and less worn parts of the stairs and obtained results indicating that the contribution of the surface, whether worn or less worn, to the risk of slipping was moderate to very low. The more worn the surface was the less slippery it was likely to be found. Dr Cooke did not make measurements of the coefficient of friction of the nosings of the steps, because by the time of his visit the nosings had been covered by the aluminium strips. 141 The results obtained by Dr Cooke were criticised on the grounds I have stated earlier in this judgment. The criticism that Dr Cooke had not adopted a proper method of proceeding (that is whether he had not used test paths giving a total of 800 mm) was not pressed at the hearing. 142 As regards the other criticisms, I accept that Dr Cooke made his measurements of the coefficient of friction more than three years after the accident and that he did not measure, because he was unable to do so, the coefficient of friction of the nosings on one of which the plaintiff slipped. However, Mr Burn observed, two weeks after the accident, that the stairs were "well-worn" and I consider that the results obtained by Dr Cooke for worn areas, even if the worn areas measured were not on the nosings of the steps, do provide guidance as to how slippery or slip free the nosings were at the time of the accident. Even the results obtained by Dr Cooke for the less worn areas were figures for the coefficient of friction of more than 0.4. 143 When Mr Burn did conduct his own tests, in 2008, of the stairs in the staircase (as distinct from the landings) he obtained only one result, on the fourth step, of less than 0.4). 144 Mr Burn did say in his oral evidence that the nosing of the step on which the plaintiff slipped could have contributed to her slipping, because, certain types of timber become smooth and polished from wear under use. However, he accepted that it would be necessary to identify the timber out of which the stairs had been made and to determine whether it was one of those types of timber which become smooth and polished as a result of wear, and neither of those steps had been taken. 145 Counsel for the plaintiff submitted that I should find that the handrail was inadequate. 146 A particular of negligence asserted in the statement of claim (par (h)) that the handrail was too "short" was not in fact pressed. I accept, as asserted by Dr Cooke, that, if the current Building Code of Australia had applied to the building including the staircase, only one handrail would have been required at a minimum height of 865 mm and the handrail on the left hand side of the staircase for someone descending the stairs would have complied with the Building Code of Australia requirements. The handrail on the right hand side of a person descending the stairs, which is the handrail which was actually used by the plaintiff was lower than 865 mm. Nevertheless I find that it provided a reasonable handhold for users of the stairs. I note that the plaintiff is a female who is not particularly tall. 147 The particular of negligence relating to the handrail which was pressed was that the handrail was rectangular, and not circular, in cross-section. I accept that this was not the optimum shape for a handrail but I find that the handrail was of a size and shape such as to enable it to be grasped. Mr Burn agreed in his evidence that, while round handrails are more common, he had seen rectangular handrails. 148 In my opinion, I should not find that there was a foreseeable risk of a person slipping on the stairs which was not insignificant, such that a reasonable person in the position of the defendants would have taken precautions against the risk. Alternatively stated, I do not consider that it has been established that the defendants failed to take such care as was reasonable in the circumstances. I find a verdict for the defendants. Damages 149 I have held that I should find the verdict for the defendants. However, in case I am wrong in so holding, I will make some findings of fact relevant to damages and consider the principal issues which were raised. Facts 150 The facts I will now state were either undisputed or were clearly established by evidence. 151 The plaintiff was born on 20 January 1965. She obtained a Higher School Certificate. After leaving school she obtained employment with a firm of jewellers and she worked for various jewellery firms up to and for some time after 24 February 2003. She obtained a qualification, a diploma of Gemmology from the Australian Gemmological Association. 152 The plaintiff married in 1990 and the marriage is still subsisting. She has had two children, born in May 1996 and November 1999. 153 In 1989 the plaintiff was involved in a motor vehicle accident. In the accident she hurt her right hip and her back. She was away from work for two weeks. Subsequently, the plaintiff from time to time had pain in her right hip and low back, for which she sometimes sought treatment from a physiotherapist. 154 On 8 December 2000 Mr Patrick Cormack, a physiotherapist who had been treating the plaintiff from time to time since at least 1990, wrote a letter in which he said that the plaintiff had seen him again with a recurrence of her back pain and some right leg pain. Mr Cormack remarked "Lina has had recurrent back problems for 10 years or more and has required treatment from time to time". 155 In December 2000 a CT scan was performed on the plaintiff's lumbar spine. It revealed at the L5/S1 level a broad-based disc protrusion causing no significant thecal deformity or nerve root impingement. 156 On 13 February 2003 Mr Cormack wrote a letter to Dr Wong, a general medical practitioner, in the following terms:- "Thank you for seeing Lina who has a recurrence of her right sciatic pain. She has a chronic back and right leg pain, but presented last Friday (7th February 2003) with a fairly significant deterioration of her condition. In particular, she reported marked paraesthesia of her right foot and leg. Examination indicated pain and restriction of trunk extension at about 20. The right straight leg raise was painful at 30. The right lumbo-sacral paravertebral region was very tender. Reflex and power tests were unremarkable, but there did appear to be some decreased sensitivity to pinprick in the right big toe. I have encountered similar episodes with Lina over many years, but on this occasion the paraesthesia was more pronounced than usual. Treatment with traction usually helps and I have already commenced this. However, there may be indications of a more marked deterioration in her condition, therefore I though that she should seek medical advice on this occasion." 157 On 14 February 2003 the plaintiff saw Dr Gorelik, a colleague of Dr Wong in the same general medical practice. Dr Gorelik's notes of the consultation dealt with a stomach complaint, which is irrelevant for present purposes, and a back complaint. A copy of Dr Gorelik's notes admitted into evidence is not easy to read but clearly refers to low back and right leg pain, recurrent L5/L4 disc prolapses and sensation in the right leg "not dermatomal distribution". 158 The plaintiff saw Dr Gorelik again on 21 February 2003. Dr Gorelik's notes of this consultation referred to the motor vehicle accident in 1989, chronic back pain and right leg numbness persisting. Dr Gorelik decided that a CT scan should be performed. 159 A CT scan was performed on the plaintiff's lumbar spine on the morning of 24 February 2003, before the plaintiff went to the defendants' premises at Erskineville. Until the first day of the hearing before me it had not been clear to the defendants that the CT scan had been performed before, and not after, the plaintiff's fall. 160 The report of the CT scan performed on 24 February 2003 stated that the L2/3, L3/4 and L4/5 discs were all delineated normally. However, the report proceeded:- "At L5/S1 there is a diffuse posterior annular protrusion encroaching upon the lateral recesses of S1 more so to the right than the left side. The right S1 nerve root is effaced. I note that the symptoms are predominantly left sided and the most likely cause is the abnormality at the L5/S1 level…" 161 It was common ground at the hearing that the reference in the report to symptoms being predominantly "left" sided was an error and should have been a reference to the symptoms being predominantly right sided. 162 The film of the CT scan performed on 24 February 2003 is no longer in existence. The plaintiff said in her evidence that she had herself destroyed it. I will return to this matter later in this judgment. 163 On 24 February 2003, after she had had the fall, the plaintiff was seen by Dr Loutfi, another member of the same medical practice as Dr Wong and Dr Gorelik. Dr Loutfi's notes record the plaintiff giving a history of having had a fall and of the plaintiff having pain in her right low back and weakness in her right big toe. 164 On 25 February 2003 the plaintiff was seen again by Dr Gorelik. Dr Gorelik's notes include that the plaintiff had had a fall down stairs at work and that on examination it was found that her range of movement in all directions was reduced. 165 The plaintiff returned to work with the firm of jewellers, Continental Jewellers, about two weeks after the fall and remained working for that firm as a general office assistant on a permanent/part-time basis until 6 June 2003. 166 The plaintiff was referred by Dr Gorelik to Dr John Sheehy, a neuro-surgeon, and she was seen by Dr Sheehy on 24 March 2003. In his report dated 25 March 2003 to Dr Gorelik Dr Sheehy said inter alia:- "She told me of the problems that had been present with low back pain intermittently since a motor vehicle accident in 1989. Her vehicle was severely damaged in the accident and she had been troubled on and off since that time. The situation changed with a flare-up of the pain in December 2002 with the development of significant right sciatica with "pins and needles" radiating into the right leg and involving the foot…" 167 In a later part of his report Dr Sheehy, after referring to earlier CT scans, said "A study performed recently, however, does demonstrate a disruption of the L5/S1 disc with compression of the S1 nerve root." This is clearly a reference to the CT scan of 24 February 2003. Dr Sheehy recommended that a MRI scan be performed. 168 It is noteworthy that in Dr Sheehy's report of 25 March 2003 there is no reference to the plaintiff's fall on 24 February 2003. 169 The conclusion in the report of a MRI scan performed on the plaintiff on 24 March 2003 was:- "A broad-based protrusion is seen at L5/S1 slightly to the right of midline with minimal displacement of the S1 nerve root on the right." 170 In a report of 3 April 2003 to Dr Gorelik Dr Sheehy said:- "Mrs Lina Youkhana's recent lumbar MR scan demonstrates persisting compression of the right S1 nerve root. Further management depends upon the clinical course. If her condition is improving, a gradually increasing exercise programme would be best. If the condition plateaus and there is persisting sciatic pain, decompression of the S1 nerve via a minimalist approach would be best." 171 Dr Sheehy performed a decompression of the plaintiff's S1 nerve root on 26 June 2003. The early reports by Dr Sheehy after the surgery spoke of the plaintiff making a good recovery. However, by the time of a report of 28 November 2003 Dr Sheehy said "initially there was marked improvement in her right sciatic pain but over the last few months, after recommencing her work, there has been recurrent pain in the low back and in the right leg". 172 At the hearing the parties were in agreement about the cause of the plaintiff's continuing medical problems, that is that the plaintiff suffered arachnoiditis or fibrosis as a result of the surgery performed on her. 173 Dr Ellis, in a part of his evidence which was not challenged by counsel for the defendants, explained arachnoiditis or fibrosis as follows:- "Arachnoiditis is a condition of fibrosis in the membranes that surrounds the spinal cord and the spinal nerve roots as they leave the vertebral canal on their way to the supply of the lower limbs and is a post-operative complication which is sometimes unexplainable. It seems to occur as an incidental unexplainable complication but it can have devastating effects and can eliminate the good effects that the operation may have had by removal of the prolapsed disc. It causes fibrosis and damage to the spinal nerve so that pain and disability continue and frequently increase and re-operation is usually avoided at all costs once that has appeared, because it gets worse." 174 Despite the plaintiff having developed fibrosis after the first surgery, she underwent three further operations, namely a laminectomy and discectomy for recurrent disc prolapse performed by Dr Loefler on 29 December 2003; a disc replacement at L5/S1 performed by Dr Diwan in February 2004; and a spinal fusion operation fusing the plaintiff's spine from L3 to S1 performed in March 2007. At the hearing there was no dissent from Dr Ellis' opinion that "each operation has been followed by a further recurrence of problems and ultimate disaster". 175 In a report in February 2006 Dr Robertson, a psychiatrist, expressed the opinion that, as a result of the failure of surgical treatment to provide lasting relief of her symptoms, the plaintiff had developed major depression. In 2006 and again in 2008 the plaintiff was admitted as an in-patient at the St John of God Psychiatric Hospital. In oral evidence at the hearing Dr Robertson said that the plaintiff's chronic pain and the failure of four surgical procedures to give relief and her consequential inability to work and inability to look after her household had precipitated and perpetuated a major depression. I accept Dr Robertson's evidence. 176 In a report in March 2008 Dr Suzanne Hodgkinson, who had seen the plaintiff in November 2007, expressed the opinion that the plaintiff had been suffering from multiple sclerosis for some time and that some of her disabilities were a consequence of multiple sclerosis. The three neurologists, Dr Watson, Dr Allsop and Dr Matheson took part in a "conclave" and gave written answers to a number of questions relating to multiple sclerosis. In answer to the question, "Do you consider that the plaintiff suffers from multiple sclerosis?" the neurologists were unable to give any more definite answer than "possible to probable". The neurologists were of the opinion that, if the plaintiff did have multiple sclerosis, neither the plaintiff's fall, nor the treatment the plaintiff had subsequently undergone, nor the stress or anxiety the plaintiff had suffered had caused or contributed to her having multiple sclerosis. 177 It was submitted by counsel for the defendants that, principally on the basis of Dr Hodgkinson's opinion, I should find that the plaintiff has been suffering from multiple sclerosis. However, having regard to the inability of Dr Watson, Dr Allsop and Dr Matheson to give any definite answer to the question whether the plaintiff suffers from multiple sclerosis, I do not consider that I should find that the plaintiff has multiple sclerosis. The credit of the plaintiff and Dr Ellis 178 I consider that I should have reservations about the plaintiff's credit. The question of the plaintiff's credit assumes greater importance on the subject of damages than it did on the subject of liability. 179 As noted previously in this judgment, the plaintiff admitted in her evidence that she had destroyed the film of the CT scan performed on 24 February 2003. She conceded, as she was virtually obliged to do, that the film of the CT scan taken only an hour or two before the fall would have been a significant piece of evidence. The reason she gave for destroying the film was that "I was told that everything was normal. The radiologist report said that everything was normal". She said that she had been told that there was "a fair bit of difference" between the CT scan of 24 February 2003 and the MRI scan of 25 March 2003 "from…normal to not normal". 180 The report of the CT scan clearly did not say that "everything was normal". There was not "a fair bit of difference" between the results of the CT scan and the MRI scan (Dr Watson said in his evidence "I think it is very much telling the same story through a different technique" and Dr Ellis gave similar evidence). It is highly improbably that any medical practitioner would have told the plaintiff that nothing abnormal was shown by the CT scan or that there was any difference of substance between the results of the CT scan and the MRI scan. 181 It was not usual behaviour of the plaintiff to destroy a piece of evidence. Dr Watson spoke of her as having brought a "dossier" of material when she saw him. 182 I find that the plaintiff realised that the film of the CT scan taken just before the fall could be significant evidence, appreciated that the film might not assist any case she brought against the owners or occupiers of the building and, having that knowledge, destroyed the film. 183 I am also satisfied that in the histories she gave to many of the doctors, particularly the medico-legal doctors, the plaintiff often downplayed the effect of the 1989 motor vehicle accident and minimised the symptoms she was experiencing before the fall. 184 As to Dr Ellis, I have reservations about whether the parts of Dr Ellis' evidence which were disputed should be accepted. Dr Ellis made two medico-legal reports on instructions from the plaintiff's solicitors and gave oral evidence. 185 It is apparent that in preparing his two reports Dr Ellis relied heavily on the history he had been given which had come, directly or indirectly, from the plaintiff. This history was defective in a number of respects, including, for example, the number of steps the plaintiff had fallen and whether the plaintiff's work in the jewellery business sometimes involved lifting heavy objects. In preparing his reports Dr Ellis did not have the CT scan report of 24 February 2003. 186 In his first report Dr Ellis under the heading "Past health" stated that "since (the motor vehicle accident in 1989) she has had slight occasional low back pain and right leg pain requiring occasional physiotherapy but it did not interfere with her lifestyle or her working ability". 187 I find that this was a serious understatement of the amount of back pain and leg pain the plaintiff had experienced, as evidenced by Mr Cormack's letter of 13 February 2003 and Dr Sheehy's first report. 188 Even this statement was qualified in Dr Ellis' second report, in which he said that the statement in the first report that the plaintiff's back had been involved in the motor vehicle accident of 1989 was not correct and her back had not been affected by the motor vehicle accident. 189 Dr Ellis' demeanour in giving oral evidence was unusual. For most of the time he was giving evidence he kept his eyes closed and held the fingers of his right hand to his forehead. 190 I consider that Dr Ellis during cross-examination was sometimes evasive and sometimes gave unresponsive answers. An example was a series of answers given to questions by counsel for the defendants as to whether some other event could have brought the plaintiff's pre-existing back condition to the point where she needed surgery. 191 Some of the opinions Dr Ellis expressed which were favourable to the plaintiff were, in my view, extreme and contrasted with the carefully expressed opinions of other doctors, for example Dr Watson and Dr Allsop. An example is Dr Ellis' evidence that "if she hadn't had the fall her symptoms would almost certainly have remained minimal". The defendants' causation argument 192 The plaintiff's case that she would be entitled to substantial damages, if she obtained a verdict, was summarised concisely by Dr Ellis in part of his evidence. Dr Ellis said "the fall required the surgery and the surgery caused the arachnoiditis" (post-operative scarring) and the plaintiff's disabilities are caused by the arachnoiditis. It was accepted that the onus was on the plaintiff to prove that chain of causation on the balance of probabilities. 193 Counsel for the defendants submitted that the onus had not been discharged and that, in particular, the plaintiff had not established that she would not have had surgery, if the fall had not happened. If the plaintiff would have come to surgery in any event, the fibrosis would have occurred, even if the fall had not happened. 194 Counsel for the plaintiff accepted that the onus was on the plaintiff to establish that she would not have had the surgery, if the fall had not happened, but submitted that the plaintiff had succeeded in discharging the onus. 195 The first operation was, of course, performed by Dr Sheehy. A number of reports by Dr Sheehy were admitted into evidence but he did not give oral evidence. There was no direct evidence in Dr Sheehy's reports on the issue of whether he would have recommended surgery, even if the plaintiff had not had the fall. 196 A further difficulty is that, as I have already stated, the plaintiff had destroyed the film of the 24 February 2003 CT scan, so that no comparison is possible of the film of the CT scan and the film of the MRI scan of 24 March 2003. 197 In support of the general submission that I should find that the plaintiff would not have had the surgery but for the fall, counsel for the plaintiff referred to a number of parts of the evidence. Counsel referred to evidence by the plaintiff that after the fall her symptoms had become more severe and constant and to evidence by the plaintiff that after the fall she had not returned to work for two weeks and that after she returned to work she worked only a couple of days a week. Counsel referred to a part of Dr Gorelik's notes of 14 February 2003 in which she said that the sensation in the plaintiff's right leg was "not (a) dermatomal distribution". It was submitted that, so long as the symptoms in the plaintiff's right leg were non-dermatomal, there was no definite evidence that a nerve root was compromised and, in the absence of such evidence, it was unlikely that a surgeon would have recommended an operation. 198 Counsel for the plaintiff referred to a part of Dr Loutfi's notes on 24 February 2003 in which Dr Loutfi recorded a complaint by the plaintiff of weakness in her right big toe. It was submitted that this was a new symptom. Counsel referred to a part of Dr Ellis' evidence in which Dr Ellis said it was likely that the plaintiff would not have come to surgery, if she had not had the fall. 199 Finally, it was submitted by counsel for the plaintiff that there was sufficient evidence to give rise to an inference in favour of the plaintiff, which could be more confidently drawn in the absence of any evidence on the issue from any doctor retained by the defendants. 200 Counsel for the defendants submitted that the onus had not been discharged by the plaintiff. Counsel referred to Mr Cormack's letter of 13 February 2003 and Dr Gorelik's notes of 14 February 2003 and 21 February 2003 in support of the submission that before the fall there had been a serious deterioration in the plaintiff's condition, including inter alia right side sciatic pain and symptoms in the plaintiff's right big toe. 201 Counsel for the defendants referred to the CT scan taken on 24 February 2003, before the plaintiff's fall, showing a protrusion at L5/S1 and that the right S1 nerve root was "effaced", that is flattened. This CT scan showed a worse position than the December 2000 CT scan, which showed no significant deformity or nerve root impingement. Dr Gorelik referred the plaintiff to Dr Sheehy on the basis of this CT scan. I have already found that the plaintiff herself appreciated the significance of this CT scan and destroyed the film of the scan. 202 The results of the MRI scan performed on 24 March 2003 were similar to the results of the CT scan. Dr Matheson that the MRI scan showed no change from the CT scan. Dr Watson said of the MRI scan "it's very much telling the same story through a different technique". Dr Ellis agreed in cross-examination that the CT scan and the MRI scan "are very much telling the same story through a different technique". 203 It was submitted by counsel for the defendants that I should not accept the evidence of the plaintiff and of Dr Ellis sought to be relied on by counsel for the plaintiff. 204 In my opinion, I should find that the onus of proving that the plaintiff would not have had the surgery but for the fall has not been discharged. 205 I find that there had been a serious deterioration in the plaintiff's condition before the fall, including right side sciatic pain and symptoms in her right big toe. The CT scan of 24 February 2003 taken before the fall showed that the right S1 nerve root had been affected and revealed a worse position than the previous CT scan taken in 2000. 206 Dr Gorelik referred the plaintiff to Dr Sheehy on the basis of the CT scan. Dr Sheehy in his first report of 25 March 2003 described the CT scan as demonstrating a disruption of the L5/S1 disc with compression of the S1 nerve root. 207 The MRI scan of 24 March 2003, which was the last radiological investigation before Dr Sheehy operated, showed much the same as the CT scan. 208 Dr Sheehy in his report of 25 March 2003 described the history, which I infer was given to him by the plaintiff, of a "flare-up" of pain in December 2002 with right side sciatica and symptoms in the right leg and foot. There is no reference in Dr Sheehy's report to the fall or to a sensation which had been non-dermatomal becoming dermatomal. 209 The credibility of the plaintiff's evidence about events happening before and after the fall is weakened by inter alia the assertions in par 31 of her first evidentiary statement in which she said:- "It has been brought to my attention that my general practitioner's notes show that very shortly before the accident I was seeing her about back pain and problems with my leg. Even though I have had a think about this I cannot specifically remember it." 210 The plaintiff's evidence that when she returned to work there was a reduction in the number of days she worked is not supported by a letter from her employer, which speaks of her working for the employer from 1 May 2000 to 6 June 2003 on a permanent/part-time basis on an average of 15-20 hours per week. 211 I have already made findings about Dr Ellis' reliability. In his reports he had expressed the opinion that all of the plaintiff's problems could be traced to the fall and in his oral evidence he appeared to me to be determined to maintain this position. 212 A consequence of my finding that the plaintiff has not discharged the onus of proving that she would not have had the surgery if she had not had the fall is that the plaintiff's damages, if she obtained a verdict, would be assessed at a quite modest figure. Counsel for the defendants submitted that there had not been any aggravation of the plaintiff's pre-existing condition by reason of the fall, beyond soft tissue injuries and soreness for a limited period. The defendants' chance argument 213 Counsel for the defendants submitted that, even if the plaintiff obtained a verdict and the defendants' causation argument was rejected, nevertheless in assessing damages allowance should be made for what was submitted was the real chance that some event other than the fall, of a kind not unlikely to happen in the ordinary course of life, would have aggravated the plaintiff's pre-existing condition and produced some or all of the disabilities from which the plaintiff suffers. Counsel for the defendants referred inter alia to Wilson v Peisley (1975) 50 ALJR at 209 per Barwick CJ; Malec v JC Hutton Pty Limited (1990) 169 CLR 638; Seltsam Pty Ltd v Ghaleb [2005] NSWCA 208 especially at [93]-[112] per Ipp JA; Lunz Assessment of Damages for Personal Injury and Death (4th ed) pars 1.9.13 and 1.9.14 at pp 110-112. 214 It was submitted by counsel for the plaintiff that the defendants had not discharged the onuses cast on the defendants by the decisions of the High Court in Watts v Rake (1960) 108 CLR 158, Purkess v Crittenden (1965) 114 CLR 164 and Malec. 215 Alternative submissions were made by counsel for the defendants that, if some allowance should be made, it should be done by increasing the amount of the discount for vicissitudes and in assessing that increased amount for vicissitudes the court should take into account that any other event, if it occurred at all, might not occur for a considerable time. 216 I accept that the defendants have not satisfied the evidentiary onus referred to in Watts v Rake and Purkess v Crittenden. While the defendants have clearly discharged the evidentiary onus, and indeed the legal onus, of proving that the plaintiff had a pre-existing condition, they have not satisfied the onus of establishing with a reasonable degree of precision what the future effects of the pre-existing condition would have been likely to be. 217 However, independently of Watts v Rake and Purkess v Crittenden, if the defendants can show that there is a real chance that some other event not of an unusual or unlikely kind could have aggravated the plaintiff's pre-existing condition so as to produce some or all of the plaintiff's injuries and disabilities, that matter should be taken into account in assessing damages. In my opinion, the defendants have succeeded in discharging that onus. I agree with the submissions made by counsel for the plaintiff that the matter should be taken into account by increasing the amount of the discount for vicissitudes and, in assessing that increased amount for vicissitudes, the court should take into account that any other event, if it occurred at all, might not occur for a considerable time. ********** DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated.