New South Wales Court of Appeal CITATION: WILKINS v COUNCIL OF THE CITY OF BROKEN HILL [2005] NSWCA 468 HEARING DATE(S): 26 September 2005 JUDGMENT DATE: 20 December 2005 JUDGMENT OF: Mason P at 1; Hodgson JA at 56; Ipp JA at 57 DECISION: Appeal dismissed with costs. CATCHWORDS: NEGLIGENCE – public swimming pool – diving accident – quadriplegia – warning signs – appeal on causation finding – whether breach materially contributed to injury – where breach was a pattern of non-enforcement of prohibition on diving – where plaintiff did not appreciate risk – whether plaintiff would have heeded prohibition had there been stricter enforcement – use of evidence of disobedient conduct – attitude towards authority - permissibility of inferring causation from breach – persuasive onus – evidentiary onus – whether analogous to medical negligence failure to warn – expert evidence – opinions outside area of specialised knowledge. (ND) Civil Liability Act 2002, s5D(3)(b) LEGISLATION CITED: Evidence Act s79 Bendix Mintex Pty Ltd v Barnes (1997) 42 NSWLR 307 Bennett v Minister for Community Welfare (1992) 176 CLR 408 Betts v Whittingslowe (1945) 71 CLR 637 Chappel v Hart (1998) 195 CLR 232 Commissioner of Main Roads v Jones [2005] HCA 27, 79 ALJR 1104 Forbes v Selleys Pty Ltd [2004] NSWCA 149 Graham v Remo Constructions Pty Ltd [2005] NSWCA 225 Inverell Municipal Council v Pennington (1993) Aust Torts Rep 81-233 CASES CITED: MacCabe v Westlock Roman Catholic Separate School District No 110 [2002] 1 WWR 610 McGee v National Coal Board [1972] 1 WLR 1 Prast v Town of Cottesloe (2000) 22 WAR 474 Rogers v Whittaker (1992) 175 CLR 479 Rosenberg v Percival (2001) 205 CLR 434 T C v State of New South Wales [2001] NSWCA 380 Vairy v Wyong Shire Council [2005] HCA 62 Wilkins v Council of the City of Broken Hill [2004] NSWSC 503 Paul Jonathan Keith WILKINS PARTIES: COUNCIL OF THE CITY OF BROKEN HILL FILE NUMBER(S): CA 40555/04 Appellant: B Gross QC/ R Wilkins COUNSEL: Respondent: J E Maconachie QC/ J C Sheller Appellant: Doyle Kingston & Swift SOLICITORS: Respondent: Tress Cox LOWER COURT JURISDICTION: Supreme Court - Common Law Division LOWER COURT FILE NUMBER(S): SC 20222/98 LOWER COURT JUDICIAL OFFICER: Bell J IN THE SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL CA 40555/04 MASON P HODGSON JA IPP JA Tuesday 20 December 2005 WILKINS v THE COUNCIL OF THE CITY OF BROKEN HILL JUDGMENT 1 MASON P: On 6 January 1996 the appellant, Paul Wilkins, dived into a public swimming pool at North Broken Hill. He struck his head on the tiled floor and suffered a spinal cord injury at C5/6 with incomplete C5 quadriplegia. 2 The North Pool was subject to the control and management of the respondent. There was an admitted duty of reasonable care to avoid the foreseeable risk of injury to users of the pool. Bell J found the respondent to be in breach of that duty in one respect. Since, however, the breach was not shown to have materially contributed to the injury, the claim failed and a verdict for the defendant was entered, with costs (Wilkins v Council of the City of Broken Hill [2004] NSWSC 503. References to the judgement below will be shown as J1, J2 etc.) Facts and the findings below 3 The accident occurred on the appellant's 14th birthday. He was approximately 6 ft tall, weighing 65 kg, having experienced a growth spurt in the previous year. He had just arrived at the complex, but he was familiar with it and the signs displayed. The main pool was 25m x 14m, with a tiled surface, a concrete perimeter surround and a raised tile border. The water was clear. It was 1.15m deep at the shallower, western end. 4 The appellant ran to the edge of that end of the pool and projected himself into the air with his left foot. In the event, the dive was steeper than he usually executed. He struck the tiled bottom of the pool on the left side of the head above the line of the top of the ear and behind the ear. 5 The particulars of negligence included complaint about failure to prohibit diving at the shallow end and failure to provide appropriate warning signs. These breaches were not established in their bald terms. There were signs stating that any person not complying with any notice was subject to removal from the facility; and warning entrants to "WALK DON'T RUN". There were also two warning signs in the vicinity of the pool referring to "SHALLOW WATER", one of them (Sign 1) being accompanied by a pictograph showing a diver about to enter the water within a red circle (see J15-17). Various criticisms of the location and content of the signs were rejected for reasons that included a finding that their putative inadequacies had no bearing on the accident. The appellant was aware of the signs and acknowledged that had he seen them on the day in question he would still have dived in the way that he did (J152-162). He said that he regarded Sign 1 as prohibiting "deep diving". 6 The particular upon which the appellant established breach of duty related to the consistency with which the Council's employees had enforced the prohibition on diving. Bell J accepted the evidence of two pool attendants that they took action from time to time to reprimand pool users over certain types of misconduct, including (on occasions) diving. Her Honour also accepted the evidence of the appellant and his witnesses that it was common for persons to dive into the pool, including at the shallow end, without reprimand by pool staff. Given that there was a risk of serious injury to a person of the plaintiff's height diving into water 1.15m deep, the learned judge concluded that the appellant had established negligence in this regard. 7 The critical findings were: 188. I do not consider that the evidence admits of the stark finding that the pool attendants habitually ignored persons diving into the pool.... 189. The lack of enforcement that is the subject of complaint is the failure of the pool attendants to reprimand pool users for having dived (the occasions on which a pool attendant might be on hand to prevent a pool user from executing a dive may not have been many). Notwithstanding the evidence of Ms Remnert and Mr De Bono [the attendants] concerning their efforts to enforce the prohibition on diving I find that it is probable that some pool attendants did not reprimand people whom they had seen diving into the pool without incident. 190. In the years and months prior to 6 January 1996 it was common for children to dive into the shallow end of the pool when the complex was open to the public generally. Any enforcement of the prohibition on diving conveyed by Sign 1 was not consistent. This was in contrast with the apparent enforcement by the pool attendants of the prohibition on other forms of potentially dangerous behaviour such as running, "bombing" and blocking the waterslide. In this respect the effectiveness of the prohibition conveyed by Sign 1 was significantly weakened. The Council could not reasonably be expected to prevent every pool user from executing a dive into the shallow end of the pool but more consistent enforcement would have served to bring to the attention of persons such as the plaintiff that this was conduct that if detected would not be tolerated. 191. The failure to take steps to ensure a more consistent enforcement of the prohibition on diving conveyed by Sign 1 with respect to young pool users seems to me to have fallen below the standard of care that the Council owed to the plaintiff in tort and as a contractual entrant to the North Pool. 8 As indicated, the appellant failed at the causation stage. The judge instructed herself that the appellant bore the onus of proving that his injuries were caused or materially contributed to by the Council's breach of duty (J192). This was a factual question to be determined by common sense considerations. The matter was to be determined subjectively in relation to the particular appellant, with caution being applied in relation to any evidence from the appellant himself as to what he would have done if the breach had not occurred (citing Chappel v Hart (1998) 195 CLR 232 at 246 and 272; Prast v Town of Cottesloe (2000) 22 WAR 474 at 489. See also Vairy v Wyong Shire Council [2005] HCA 62 at [226]). I do not understand the appellant to suggest legal error in her Honour's general approach. 9 Bell J commenced by recognising that the appellant was aware of the sign warning about "SHALLOW WATER" and the no diving pictograph. She adverted in this context to the appellant's evidence about his understanding of the pictograph and his suggestion that he would have heeded a different warning sign (J193-4). The judge found the appellant to be "an essentially honest witness" (J193), but correctly observed that his evidence on this topic needed to be assessed with some circumspection. 10 The judge then turned "to look to the evidence concerning the attitude and conduct of the plaintiff as at January 1996 in order to determine whether the Council's failure to enforce a prohibition on diving at the shallow end of the pool was causative of his injury" (J197). Particular evidence was summarised. The appellant was a high-spirited young teenager who conceded that he was not compliant with instructions given to him by pool attendants (J198). The judge also set out (J199) a significant passage of cross-examination in which the appellant acknowledged that the risk of serious injury from diving in the shallower end was "pretty obvious" and that he knew that diving into a pool where the water was shallow was dangerous. 11 Her Honour referred to some of the appellant's somewhat unsatisfactory school reports, describing them as evidence of his behaviour around the time of the accident. She observed that this evidence was not without significance in deciding whether to accept the appellant's evidence (at Black 39) that, had he seen a no diving pictograph accompanied by the words "no diving" at the shallow end of the pool, he would not have dived into it (J200-1). By implication, she was not persuaded to accept this evidence, not that it was the breach found established. The judge referred in this context to evidence from the appellant showing that he used to run around the pool despite clearly knowing this to be against the rules (J202-3). issues raised by appellant 12 The appellant accepts the finding of negligence made by the primary judge, while contending that her Honour erred as to causation. 13 The grounds of appeal and written submissions are very discursive. Most of them restate the arguments advanced at trial. This latter point is not a criticism, given that the appeal is by way of re-hearing. This said, I state at the outset that I am unpersuaded of any legal or factual error in her Honour's reasoning, having given close attention to Mr Gross QC's earnest submissions in this tragic case. 14 The appellant correctly emphasises that the proper starting-point for addressing causation is the breach that was found. The nub of that breach was that the impact of the warning about shallow water and the prohibition upon running and diving, communicated by the signs and occasional remonstrations by attendants, was dulled by the widespread pattern of non-enforcement as to diving. This conveyed a message that the danger was not as serious as it potentially was. In fact, the potential consequences were catastrophic, something that the Council knew or ought to have known, in contrast to the appellant himself whose appreciation of the true risk was clouded by youthful ignorance and optimism (see generally Inverell Municipal Council v Pennington (1993) Aust Torts Rep ¶81-233). 15 It was further submitted that the appellant was a high-spirited youth who has shot up in height in the months preceding the accident. He and those he observed had dived into the pool on many occasions, without being checked for this by the attendants. His claimed interpretation that the "no diving" pictograph prohibited only "steep diving" and his contention that causation was established were said to draw reinforcement from (a) the passive attitudes of the attendants, (b) the practice of other pool users and (c) the fact that the appellant had himself dived many times with no more serious injury than a scratch on the nose. For a youth of the appellant's size there was unfortunately only a small margin of error between a safe dive and the one executed on the day in question. 16 These submissions place proper emphasis upon the factual content underpinning the uncontested finding of breach. That finding is the starting point for analysing the causation issue. This proposition has consequences that need to be borne in mind. 17 First, the Council is to be held legally accountable only for what it negligently failed to do. It was common ground, both at trial (J190) and on appeal, that it was well-nigh impossible and certainly not negligent per se to fail to prevent each and every entrant from diving into the pool. 18 Secondly, the causation question is what did the plaintiff show would probably have happened on his part had the negligence not occurred. This was necessarily a hypothetical question. Furthermore, as her Honour observed, it required the Court to determine what the particular plaintiff would (subjectively) have done if there had been adequate performance of the defendant's duty. 19 Contrary to the grounds of appeal 1, 3, 11 and 13, there is an abundance of material showing that, when considering causation, Bell J (correctly) focused upon the breach of duty that had been found, a breach she described in shorthand as the failure to enforce a prohibition on diving at the shallow end. See J192, 197, 204, 207, 214, 215, 219. This is exemplified by a significant passage in the reasons revealing the attention being paid to the particular case being advanced by the appellant in this context: 204. The plaintiff's case is that it is no answer to say that he was a strong willed and disobedient youth and to infer from this that he would not have been deterred from diving despite more active enforcement of the prohibition on it nor to point to his acknowledgement that he knew that diving into shallow water could be dangerous. In Mr Gross'submission he was a child who lacked appreciation of the risk of severe injury. In the event that the Council had taken more active steps to enforce the prohibition on diving there is no reason to conclude that he would still have dived on this day. His decision to do so reflected an accepted practice of entering the pool at the shallow end by diving.... 207. In Mr Gross' submission the repeated supervisory failures by the pool attendants had an additive and synergistic effect. He contended that the plaintiff became increasingly assured that it was reasonable and safe to dive into the shallow end of the pool. The belief became progressively more entrenched and produced a growing confidence in his ability to do so. He was said to be vulnerable to error because of a lack of appreciation of the significance, in terms of safety, of the rapid increase in his height and weight that he had undergone in the previous year at the age of 13...." 20 Merely because the judge stated (at J218) that she did not accept that had the appellant seen a sign such as those subsequently installed at the North Pool he would have heeded the prohibition. This alone does not demonstrate the error contended for. This was a single plank in a whole body of reasoning. Her Honour was addressing the impact of specific evidence led from the appellant himself (at Black 39). 21 Nor did the judge fail to appreciate that the Council's conduct may have led the appellant to perceive that although diving was formally prohibited and risky it was permitted in practice. The findings of breach recognised explicitly that the Council had failed to do enough to enforce and re-enforce the warning and prohibition, especially for young people. These findings were specifically addressed in the causation context in the passages referred to above (see, eg, the reference to "repeated supervisory failures by the pool attendants" allegedly having had an additive and synergistic effect). 22 Unfortunately for the appellant, he did not persuade the trial judge that he would not have dived as he did had there been a stricter, non-negligent regime of warning/enforcement directed at him and pool users in general. This is a conclusion not shown to be affected by error of law or fact. 23 I do not accept the submission (Ground 2) that the findings on causation were inconsistent with Bell J having rejected the volenti defence. That defence failed for the following reason: 228. I accept that the plaintiff may have understood that there was some risk of injury associated with diving into the pool at the shallow end, however, I do not find that he appreciated that he risked permanent injury of the kind that he sustained as the result of diving into the pool or that he agreed to accept that risk and bear the legal consequences of such an injury. In this respect I am mindful that the plaintiff had just attained his fourteenth birthday. While not of tender years he was nonetheless a child. His ability to appreciate the risk and to voluntarily accept the legal consequences of doing so seem to me to have been reduced because of his immaturity. 24 This passage recognises that appellant did not fully appreciate the risk he was taking. It does not follow that such a state of mind was caused or materially contributed to by the Council's negligent conduct. 25 The judge acknowledged (at J208) the written submission on behalf of the appellant that there was insufficient evidence to support a conclusion that in the absence of the many repeated breaches of duty by the pool attendants over a long period, the appellant would still have been injured in the same manner. At trial, and in this Court, the appellant invoked the well known passage in the judgment of Dixon J in Betts v Whittingslowe (1945) 71 CLR 637 at 649, together with later statements as to the permissibility in certain circumstances of inferring causation from breach (J208-215). These included Gaudron J's remarks in Bennett v Minister for Community Welfare (1992) 176 CLR 408 at 420-1. 26 Her Honour was prepared to accept the applicability of these principles (see J215). Nevertheless, she reasoned towards the ultimately adverse conclusion in the following terms: "215. [It] seems to me that the evidence of the plaintiff's disinclination to comply with rules makes it difficult for him to prove the causal link between the failure to enforce the diving prohibition with greater consistency and his injury on this day. 216. The plaintiff was aware of the signs saying, "walk don't run" near the entry to the North Pool. He understood that he was not to run around the pool. He had previously been admonished by pool attendants for running at the pool and on one occasion he had been asked to leave because of this conduct. He understood that the prohibition on running on the concrete pool surround was because of the risk of injury from falling. Nonetheless from time to time he did run on the concrete pool surround. 217. On occasions the plaintiff engaged in other activities that he knew to be prohibited including blocking the water slide and climbing onto the back of other swimmers. He understood that this was behaviour for which one could be asked to leave the pool complex. 218. I do not accept that had the plaintiff seen a sign such as those subsequently installed at the North Pool bearing the words "no diving" he would have heeded the prohibition. Had the prohibition on diving been enforced with the same consistency as the prohibition on "bombing", climbing on the backs of swimmers and on running was enforced by the pool attendants, I am not persuaded that it is likely that the plaintiff would not have dived into the shallow end of the pool on this day. The dive was a running dive. I am satisfied both that running across the concrete pool surround was prohibited by notice and that the prohibition was actively enforced by the pool attendants. 219. I am unpersuaded that the evidence supports the inference that the repeated failure to enforce the prohibition on diving can be said to have led the plaintiff to believe that it was safe for him to dive. While some of those who gave evidence were not aware of the no diving pictograph at the shallow end of the pool, the plaintiff was not one of them. I am satisfied that at the age of 14 he understood the sign to mean that diving was prohibited. 220. I have concluded that the Council's breach of duty in failing to enforce with greater consistency the prohibition on diving into the pool at the shallow end did not materially contribute to his injury. 27 Some grounds of appeal state or imply that her Honour erred in law in relation to the causation issue. 28 Thus, grounds 8, 9, 10 and 10A allege error in law, in effect for having failed to draw an inference of causation based upon the legal principles stated by Dixon J in Betts and Gaudron J in Bennett. There was no such error, because the inference was not compelled and because her Honour applied correct legal principles. 29 To the extent that these submissions flirt with the proposition that there is some reversal of the persuasive onus of proof in causation matters they should be rejected. My understanding of the applicable principles remains as stated in T C v State of New South Wales [2001] NSWCA 380. I there indicate why I cannot accept the argument that the remarks of Gaudron J in Bennett stand for the proposition that there is some reversal of the legal onus in certain circumstances (cf Ground 10). See also Forbes v Selleys Pty Ltd [2004] NSWCA 149. As Bryson JA recently observed, "what is involved is not a principle of law but a line of reasoning on causation for consideration by the tribunal of fact" (Graham v Remo Constructions Pty Ltd [2005] NSWCA 225 at [24], Mason P and Hislop J concurring). 30 Betts indicates what a tribunal of fact may do in inferring causation in a limited category of cases. Bell J recognised this and was prepared to assume in the appellant's favour that it was open to infer causation in the present case (J215). She was not persuaded to do so, having regard to all of the circumstances. In effect, she treated the material adduced in relation to the appellant's attitude to rules, including safety rules at the pool, as "sufficient reason to the contrary" (cf Betts at 649) that led her to reject the causation case on the probabilities. This approach to the causation question was correct in law (see also Commissioner of Main Roads v Jones [2005] HCA 27, 79 ALJR 1104 at [10], [26], [80]-[81]). 31 Her Honour correctly recognised that the present case was one in which the plaintiff retained the ultimate onus. She recited the relevant material, including the plaintiff's testimony (contrast now Civil Liability Act 2002, s5D(3)(b)) and the evidence tending to show his attitude towards rules in general and the safety rules at the swimming pool in particular. 32 The evaluative conclusion that her Honour was not persuaded that causation was established was well open to her and has not shown to be wrong on the facts. As I observed in Forbes (at [107]), robust and pragmatic decisions on causation are not always made in the plaintiff's favour. 33 It was submitted that the judge wrongly rebuffed the assistance of Betts in her remark that the present case did not give rise to difficulties in proof of causation of the sort with which the Courts were concerned in Betts, McGee v National Coal Board [1972] 1 WLR 1 or Bendix Mintex Pty Ltd v Barnes (1997) 42 NSWLR 307 because (J214): …The plaintiff's accident is not an unexplained event. He dived into the pool knowing the depth of water at the shallow end and being aware of Sign 1. However, I have found that the Council was in breach of the duty that it owed the plaintiff by its failure to enforce the prohibition on diving at the shallow end of the pool with greater consistency. 34 It is, with respect, a little unclear what the judge had in mind in her reference to an "unexplained event". The accident and its mechanics were established on the evidence. What was in issue was the probable impact of the defendant's breach. This is always "unexplained" in the sense that the court is involved in a hypothetical inquiry as to what the particular plaintiff would have done had things been otherwise. I infer that her Honour was making the point that the case differed from the factual starkness of the cases cited in that there was a significant body of material that provided assistance in determining whether the persuasive onus was established in the particular case. Bell J did not suggest that this precluded resort to the reasoning process discussed in the authorities she cited. Her point was that the evidence, which supported the defendant's position, made it "difficult" for the plaintiff to prove the ultimate causation issue. 35 Recognition of the matter referred to in the preceding paragraph does not persuade me that the decision as to causation was wrong in its conclusion. 36 A second cluster of suggested legal issues was raised in grounds 3 and 12. 37 In these grounds the appellant advances two related propositions. First, he submits that the judge erred in treating the case as analogous to a medical warning case such as Rogers v Whittaker (1992) 175 CLR 479. The causation issue involved where a doctor negligently fails to warn or give advice as to the possible impact of a procedure involves inquiry as to the probable response of the particular patient had the particular information been conveyed. By contrast, in the present case, it would be wrong to have considered no more than this plaintiff's likely response to the prohibitions/warnings contained within the signs at the pool if this occurred in isolation from his attitude engendered by the whole pattern of tepid reinforcement involved in the finding of breach made by her Honour. I entirely agree, but part company with the appellant at the point where it is suggested that her Honour may have fallen into this error. I have already indicated why her Honour's causation reasoning does not involve this suggested fallacy. Nor does it contain the particular variant of it suggested in these grounds of appeal. 38 Her Honour's reference to a passage in McHugh J's judgment in Chappel (at J213) was in the context of acceptance that there will be some cases in which an evidentiary onus rests on a defendant to point to evidence suggesting the absence of a causal connection. 39 The appellant is wrong to suggest that the causation inquiry in the present case did not involve any assumed hypothesis (Written submissions at §181). The hypothesis that had to be assumed was that the Council had performed its duty of care and not breached it, as established. 40 Secondly, it was submitted that the judge erred in law by elevating a mere speculative possibility (ie that in the absence of the defendant's breach of duty, the plaintiff would still have dived into the shallow end of the pool in precisely the same manner causing the same injuries) into a probability, when such reasoning and conclusion was not warranted on the evidence. This is really a complaint about the facts dressed up as one suggesting error or law. 41 In Chappel, McHugh J stated some general propositions concerning the onus of proving causation in a case involving a defendant's negligent failure to warn of a risk of injury. The passage confirms that the persuasive onus rests throughout upon the plaintiff, while recognising that the defendant may bear an evidentiary onus in some circumstances. His Honour said (at 247[34]): [O]nce the plaintiff proves that the defendant breached a duty to warn of a risk and that the risk eventuated and caused harm to the plaintiff, the plaintiff has made out a prima facie case of causal connection. An evidentiary onus then rests on the defendant to point to other evidence suggesting that no causal connection exists. Examples of such evidence are: evidence which indicates that the plaintiff would not have acted on the warning because of lack of choice or personal inclination… Once the defendant points to such evidence, the onus lies on the plaintiff to prove that in all the circumstances a causal connection existed between the failure to warn and the injury suffered by the plaintiff. 42 McHugh J was in dissent in Chappel, but not on the issue addressed in this passage. 43 The passage directly supports the primary judge's approach to the factual inquiry involved in the causation question. The matters considered by her Honour included the appellant's behaviour at the pool, his compliance with rules generally and the rules concerning running and diving at the pool in particular (see J104-110, 216-7). These were properly treated as relevant to the ultimate issue. They were part of the evidentiary material adduced by the Council pursuant to the evidentiary onus referred by McHugh J in Chappel and the other cases in the Betts line. 44 In MacCabe v Westlock Roman Catholic Separate School District No 110 [2002] 1 WWR 610 the plaintiff was rendered quadriplegic following an accident in a gymnastics class. The trial judge found that the teacher who supervised the class did not provide adequate instructions or clear prohibitions on relevant conduct, which negligence was found to have contributed to the accident. The causation finding was unsuccessfully challenged in the Alberta Court of Appeal. It was there pointed out that a plaintiff did not have to establish that the School's negligence was the sole cause of the injury. The negligence in that case was analogous to that found in the present case, in that several matters combined both to establish negligence and arguably to induce the plaintiff to perform the manoeuvre in which she was injured. In MacCabe, this included provision of crash mats creating a false sense of security, lack of instructions, failure to forbid the particular manoeuvre, lack of supervision, failure to stop students from attempting the manoeuvre and instructions to students to be "creative" in their gymnastics. Speaking for the Court of Appeal, Wittmann JA approved the following statement by the trial judge on the causation issue (at 276-7): The presence of any one of the breaches as noted above was itself sufficient to have caused the accident. However, these breaches appear to have combined in a synergistic manner such that each of the breaches augmented the others and this synergistic interaction in my view placed the Plaintiff at risk. For example, although the presence of the crash mat at the box horse station and Romanuik's failure to take students through their proper progressions were each breaches of the standard of care, when these two factors were combined, they worked together to increase the degree of risk of injury. Add a third factor, the environment Romanuik created by instructing the students to be creative and that they would be graded on this creativity, enhancing their already competitive spirit, the risk is augmented yet again. Therefore, although I find that any one of the identified breaches would clearly reach a causal threshold beyond a balance of probabilities, if one further considered the straight additive effect of the breaches, it is taken well beyond that threshold. 45 I do not accept the appellant's submission that Bell J failed to apply these principles. Her Honour considered the whole range of conduct attributable to the Council that justified the finding of negligence. 46 The appellant is critical of the "undue reliance" placed by Bell J on the evidence about his disobedient conduct at school (Grounds 4, 7, and 10A). There was a significant body of material in the form of reports by teachers, letters to the appellant's mother, records of two suspensions for misconduct and cross-examination of the appellant about his behaviour at school. Bell J observed (J136): He agreed that he had regularly misbehaved at school. He had been counselled about misbehaviour and his mother had been asked to come to the school to discuss his misconduct. Despite this record he continued to misbehave. He was suspended from school on two occasions in 1995. These resulted in one case from talking, joking and mucking around in class and on another occasion for smoking. 47 At trial, the appellant's counsel had submitted that the school material provided little assistance in determining the likelihood of him diving into the shallow end of the pool had the Council not been in breach (J200). Bell J did not accept this proposition (see J201). 48 Her Honour correctly recognised that, for the appellant, poor behaviour did not indicate lack of intelligence. But the matter in issue was the appellant's attitude towards rules and persons in authority, to the extent that his school experience could be extrapolated to the vital hypothetical question touching the probability of whether the appellant would not have dived on the day of the accident had it not been for the Council's prior negligence. This was the correct focus and the school material was, in my opinion, capable of casting some light upon the issue. 49 Ground 14 contends that Bell J erred in rejecting the expert evidence of Mr Richard Lightfoot, a consulting engineer. Each party relied solely upon the written submissions addressing this ground of appeal. 50 Mr Lightfoot gave evidence in the case and on the voir dire referable to the admissibility of the report. Bell J ruled that some of the expert's opinions were admissible, but some were not (Black 249). The portions rejected related to opinions expressed concerning the effectiveness and impact on behaviour of the warnings in Sign 1. Bell J ruled that these opinions were not based on the witness's specialised knowledge and were therefore outside the area of his established expertise. 51 Mr Lightfoot had qualifications and experience connected with the mining industry although he had practised more widely than that. For a time he was Chief Engineer (Antarctic Division) responsible for all aspects of the engineering program in the Antarctic and the support operations mounted from Australia. During the past 20 years his consulting engineering practice had provided specialist advice to company projects, including industrial accidents, environmental and pollution, mechanical and electrical engineering construction and operation, vehicle, plant equipment and machinery operations. He had provided expert engineering advice on aspects of manual handling and risk assessment for safety in the workplace. 52 Signs are infinite in their variety and impact. The Court was not taken to any evidence indicating that this witness's expertise extended to semiotics or psychology. The fact that he was called to give evidence, in effect, on the ultimate issue was not in itself a disqualifying factor. But it called for scrutiny in determining whether s79 of the Evidence Act was satisfied. No error has been shown in the rejection of this evidence. 53 I do not accept the appellant's submission that her Honour gave undue or inappropriate emphasis to the material concerning the appellant's behaviour at school. Nor did she err in the use made of the material relating to the appellant's "non-compliant" conduct on earlier occasions at the pool (cf Grounds 3, 4, 5, 6, 7, 7A and 12). 54 The trial judge had the advantage, compared to this Court, of having seen the appellant give evidence over a period of days. Her conclusion as to the probability that the fateful dive would still have occurred had there been no negligence is partially informed by the impression she drew from having seen the appellant giving his evidence. Rosenberg v Percival (2001) 205 CLR 434 (esp at 446-8, 486-7) shows that a conclusion stemming in part from this perspective is not lightly to be displaced on appeal. 55 The appeal should be dismissed with costs. 56 HODGSON JA: I agree with Mason P. 57 IPP JA: I have had the privilege of reading the reasons of Mason P in draft and I agree with them and the order proposed. ********** 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.