Reported Decision : 47 NSWLR 405 New South Wales Court of Criminal Appeal CITATION : Regina v Leung and Wong [1999] NSWCCA 287 FILE NUMBER(S) : CCA 60825/98; 60834/98 HEARING DATE(S) : 30 July 1999 JUDGMENT DATE : 15 September 1999 PARTIES : REGINA v Jackie Kai Cheu LEUNG REGINA v Nelson Tak Fat WONG JUDGMENT OF : Spigelman CJ at 1; Simpson J at 2; Sperling J at 66 LOWER COURT JURISDICTION : District Court LOWER COURT FILE NUMBER(S) : 98/11/0134; 98/11/0132 LOWER COURT JUDICIAL OFFICER : Blanch DCJ COUNSEL : Crown: K A Chapple Leung: G D Wendler Crown: Commonwealth DPP SOLICITORS : Leung: Dan Houten Wong: Hovan & Co. CATCHWORDS : CRIMINAL LAW; Importation of commercial quantity of heroin contrary to s 233B Customs Act 1901; Opinion evidence at trial admissable and properly admitted pursuant to s 79 Evidence Act 1995; Appropriate directions given by trial judge in relation to Leung's failure to give evidence; Appeal against convictions dismissed. Evidence Act 1995 ACTS CITED : Criminal Appeal Act 1912 Customs Act 1901 R v Smith ([1983] NSWLR 462, ((1986) 7 NSWLR 444) Bulejcik v R ((1996) 185 CLR 375) R v Menzies [1982] 1 NSLR 40 CASES CITED: R v Butera (1987) 164 CLR 180 R v Eastman (1997) 158 ALR 107 R v Cassar and Cleiman, unreported [1999] NSWSC 436, unreported. Weissensteiner v R (1993) 178 CLR 217 R v O G D (1997) 98 A Crim R Jones v Dunkel (1959) 101 CLR 298 DECISION : Both appeals against conviction dismissed IN THE COURT OF CRIMINAL APPEAL 60825/98 60834/98 SPIGELMAN CJ SIMPSON J SPERLING J Wednesday 15 September 1999 REGINA v Jackie Kai Chu LEUNG REGINA v Nelson Tak Fat WONG JUDGMENT 1 SPIGELMAN CJ: Subject to one matter, I agree with the judgment of Simpson J. It is unnecessary to decide the case on the basis of s78 of the Evidence Act. Like Sperling J, I would reserve my position as to the scope and effect of the section. ********** SIMPSON J : 2 On 10 August 1998 the appellants Leung and Wong were jointly indicted on a charge that between 1 October 1997 and 8 November 1997 they were knowingly concerned in the importation into Australia of not less than the commercial quantity of heroin, contrary to s 233B of the Customs Act 1901. Each appellant entered a plea of not guilty. On 7 September 1998 after a trial lasting almost four weeks the jury returned a verdict of guilty in each case. On 18 December 1997 Davidson DCJ sentenced the appellants identically to imprisonment for twelve years with a non parole period of seven years, the sentences to commence on 8 November 1997, the date on which the appellants were arrested. A third person, Ngai Sze (also known as Edwin) Law, pleaded guilty to a similar charge and was sentenced by Blanch CJ of DC on 5 August 1998 to imprisonment for ten years with a non parole period of six years. Each appellant appeals his conviction. 3 Wong and Law seek leave to appeal the severity of the sentences imposed. The Crown appeals the asserted inadequacy of all sentences. The sentence appeals were heard by a differently constituted bench. 4 Three grounds of appeal against conviction were pleaded and argued on behalf of Leung. Wong, who appeared in this court unrepresented, purported to rely upon the arguments advanced on behalf of Leung. For reasons that will appear this position was misconceived. There was, in effect, no relevant ground of appeal raised or argued in relation to Wong's conviction. The Crown Case 5 The Crown case can be stated as follows. On 31 October 1997 airfreight that included five wooden packing cases each containing one marble pedestal consigned from Bangkok arrived in Adelaide. All were marked for delivery to the same Adelaide address. The unopened crates were intercepted by Australian Federal Police and Customs Officers and taken to police headquarters in Adelaide, where they were x-rayed. Each pedestal was shown to contain a hollowed out section containing packages which later analysis proved to be heroin. In all there was 13.46 kg of powder, amounting to 9.356 kg of pure heroin. The pedestals remained in police custody until 3 November 1997. During that time each pedestal was dismantled and the heroin extracted and replaced with a substance mostly made up of plaster of paris but containing a small amount (5 gm) of heroin. In one of the pedestals, numbered 3, police installed sound recording and transmitting equipment. The pedestals were then reconstituted and returned to the air cargo office where they were claimed on 5 November by a man called Yu S Cheng who arranged for their delivery to the address on the crates later that afternoon. The pedestals were removed from their crates and transported from Adelaide to Sydney in a rented four wheel drive vehicle. Police maintained surveillance of the pedestals from the time they left the air cargo office, and maintained surveillance of the vehicle to which they were transferred throughout a journey from Adelaide to Sydney. 6 Eventually the pedestals were unloaded and late in the evening of Friday 7 November were placed in the garage of a house in Ivy Place, Cherrybrook. These premises were owned by Law's parents. After the pedestals were placed in the garage the garage doors were closed. Police maintained surveillance of the premises during the remainder of that night and the following day. At about 3.30 am on Saturday 8 November police installed video recording equipment focussed on the garage. This was connected with the audio equipment already installed in one of the pedestals. The sound was recorded both on a digital audio tape recorder and on the sound recording system of the video recorder. From late on the Saturday afternoon the video and sound recording devices were activated. The video recording depicted, inter alia, Wong shirtless inside the garage placing a cardboard screen in front of the window. The recording from the audio devices secreted in pedestal no.3 contained sounds consistent with the smashing of the marble pedestals with heavy tools or implements. Also recorded was a conversation in Chinese languages. This tape recording which, together with a transcript of a translation, became exhibit 16, was referred to from time to time as "the DAT tape", or "the garage tapes" terminology that I shall continue to use. Assuming the translation is accurate, it incontestably contains material incriminating its participants. It is sufficient at this point to note that the conversation makes it clear that the participants had discovered the substitution of the plaster of paris for the heroin. Some of the conversation might reasonably be interpreted as concerned with the price of heroin. 7 At 7.00 pm police executed a search warrant, entering through the front door of the house. Present in the house when they did so were Wong, Leung and Law and nobody else. A large number of items of different kinds were seized. These included at least two mobile telephones. On the garage floor and in a plastic bag were the smashed remains of the marble pedestals. In the roof area were the five packages that had been placed in the pedestals by police in Adelaide. 8 That evening Federal Agent Lisa Richards had a number of conversations with Leung. The first, of short duration, took place at the Cherrybrook premises. This conversation was wholly in English. Three conversations, one of them about ten minutes in length, took place at Australian Federal Police headquarters in Sydney, with a Federal Agent named Kam acting as interpreter for Leung. The fifth conversation, later in the evening, which was very short and at which a different Federal agent interpreted, took place after Leung had been visited by his legal representatives and had received legal advice. He declined to participate in a record of interview. Each of these conversations was recorded by Federal Agent Richards using a hand held recorder. 9 Two conversations with Wong, entirely in English, the first at the Cherrybrook premises and the second at Australian Federal Police headquarters, were similarly recorded. These tape recordings became known as "the police tapes". I shall continue at times so to refer to them. 10 An interpreter, Mr Keith Fung, was retained by Australian Federal Police to translate the content of the DAT tapes. He provided a transcript in English of the conversation. In the transcript Mr Fung isolated three different voices, which he nominated for the purpose of the transcript as "M1", "M2", and "M3". There is no ground of appeal that challenges the evidence given by Mr Fung in this regard. 11 However, Mr Fung was asked to go further and allocate the voices so nominated to the two appellants. He did so by comparing the DAT tapes with the police tapes. It is this evidence which is the foundation for the first and second grounds of Leung's appeal, and to which it will be necessary to return. The Defence Cases 12 Leung did not give evidence in the trial. The trial judge gave directions to the jury about his silence which are the foundation for his third ground of appeal. 13 Wong did give sworn evidence. His account, properly analysed, amounted to an acknowledgment that he and Leung had been present at the Cherrybrook premises, and that he had assisted Law in some minor respects, but that he had been an unwitting and unwilling participant. He admitted that he had known that the pedestals contained drugs, but denied knowledge of the actual drug, and denied participating in its removal from the pedestals. That is, the essence of his defence was a denial of the element of knowledge that is essential to the charge. 14 Wong said that on 8 November 1997 he went with Leung to a Honda dealer on the North Shore. While there, at about 4.00 or 4.30 pm he received a telephone call from Law who was his best friend. Law sounded anxious but did not explain the cause of his concern. At Law's request, Wong went to Law's house, accompanied by Leung, although Wong thought that Law did not then know that Leung was in his company. They arrived at about 5.15 pm. On arrival, Law took him into what Wong described as "the computer room". Law told him that he had a serious problem and asked Wong to assist him to break the pedestals and take something from them. Law said that if the police became involved he would be in great trouble and he and his younger brother might die or be killed or hurt. Law appeared to be very frightened and was crying. Wong said that Law took him to the garage, although he (Wong) protested and said that he did not want to be involved. Law begged Wong to help. Law asked him to screen the window with the cardboard. Wong did not know why but could guess. He did not see what was in the pedestals and did not want to know but Law told him that it was a drug. He was not interested and did not know which drug. Later he helped Law with some cleaning up in the garage. 15 Notwithstanding this evidence Wong maintained that he had nothing to do with the handling of the heroin, that his presence at the house was not connected with the importation of heroin, and that, in doing what he did to help Law, he did not intend to facilitate the importation. He denied having any conversation about the price of heroin while acknowledging Leung's presence, he consistently gave negative responses when asked if Leung were in the same room, or in the immediate vicinity, or present at particular conversations. 16 One significant aspect of his evidence to which attention should be drawn was his claim that two or three other people, besides himself, Leung and Law, were present in the house. One was a man he identified only as "Peter". He said these people were in the garage but closed the door. A sketch plan of the house in evidence shows that the garage opens into another room described as a "sunken lounge room". Wong said that he spent some of his time in this or another room of the house and that the other people were in the garage. They were not present when he and Leung assisted Law to clean up the garage. There was no other evidence either in the Crown case or the defence case to confirm the presence of others. The Grounds of Appeal The Leung Appeal Grounds 1 and 2 17 Leung's first and second grounds of appeal are framed as follows: "1. That the Learned Trial Judge erred in law by ruling that the evidence of Mr Keith Fung, concerning voice identification and voice comparison, was admissible. 2. That the Learned Trial Judge erred in law by holding that the witness, Mr Keith Fung was sufficiently qualified to give expert opinion evidence concerning voice identification and voice comparison." 18 It is now necessary to say a little more about the circumstances in which the evidence of voice identification was given. Mr Fung is a highly qualified and experienced interpreter, proficient in both Mandarin and Cantonese. Initially he was asked to provide a translation of the DAT tapes or garage tapes. He said the language used was predominantly Cantonese, but there were occasional Mandarin expressions, as well as some expressions in another dialect, possibly Shanghainese, that he was unable to decipher. In a voir dire examination Mr Fung said that, in listening to the tapes, he distinguished the three different voices which he nominated as "M1", "M2", and "M3". He reached this conclusion by evaluating the pitch and the volume of the voices, and the speed of the language used. He said the speaker he nominated as "M1" was a Cantonese speaking person with a medium to high pitched voice and spoke relatively quickly. (In the evidence he gave before the jury, he described this voice as of medium pitch.) "M2" was a person who spoke accented Cantonese as though that language was not his mother tongue, also in a medium to high pitched voice, but at a relatively low volume. This speaker spoke some sentences in Mandarin. "M3" was a Cantonese speaker with a relatively high pitched voice. There was a fourth voice Mr Fung heard when a mobile telephone was answered. He was unable to describe this voice in more detail, having heard only odd words from the speaker. Mr Fung performed this exercise over a period of about 15 hours during November and December 1997. 19 Later, only a week before the trial, Mr Fung was asked to listen to the tape recordings of the conversations between each of the appellants and the Federal agents referred to in paragraphs 6 and 7 above, to compare the voices on those tapes with those on the DAT tapes, and express an opinion as to the identity of the voices on the DAT tapes. Having done so, he concluded that the voice he had nominated as "M1" was the voice of Leung and the voice he had nominated as "M3" was the voice of Wong. It is this evidence that is in question in these grounds of appeal. 20 Mr Fung's qualifications as an interpreter were not in issue. There were two aspects to his opinion evidence. The first was the expert evidence he gave of the translation of the contents of the DAT tapes. There is in this court no challenge to that evidence which is properly characterised as expert opinion evidence and admissible by s 79 of the Evidence Act 1995. 21 The second aspect of his evidence is his attribution, following his comparison of the voices on the two sets of tape recordings, of two of the voices on the DAT tapes to the two appellants. It was conceded by the Crown at the trial that this was opinion evidence, in an area in which Mr Fung did not possess relevant specialised knowledge based on training, study or experience. Indeed, during cross-examination on the voir dire, Mr Fung volunteered that he was not a voice expert, but said that he had done his best to identify the voices. He pointed out the difficulty of describing voice characteristics as distinct from recognising familiar voices. 22 Objection was taken at the trial to the admission of the evidence. The challenge on appeal is essentially the same as the objection then taken. 23 Mr Fung's evidence in this regard was admitted on the basis that it was an expression of a lay opinion as provided by s 78 of the Evidence Act. It is this aspect, and only this aspect, of his evidence that is challenged in this appeal. 24 The trial judge stated his approach to the question of admissibility as follows: "If the Crown's case is to be supported by this sort of evidence from Mr Fung it must be on the basis of s 78, that is to say, as a lay opinion expressed by Mr Fung following his comparison of the two sets of tapes." 25 His Honour then referred to the decisions of O'Brien CJ of Crim D in R v Smith ([1984] 1 NSWLR 462) and the decision of this Court in the same case on appeal ((1986) 7 NSWLR 444) and that of the High Court in Bulejcik v R ((1996) 185 CLR 375). All these decisions concerned the pre-Evidence Act admissibility of voice identification evidence. It will be necessary to return to a consideration of these decisions. They are not, in my opinion, relevant to the question whether the evidence was rendered admissible by s 78. S 78 of the Evidence Act . 26 S 78 provides as follows: "The opinion rule does not apply to evidence of an opinion expressed by a person if: (a) the opinion is based on what the person saw, heard or otherwise perceived about a matter or event, and (b) evidence of the opinion is necessary to obtain an adequate account or understanding of the person's perception of the matter or event." 27 "The opinion rule" referred to in the opening words of the section is contained in s 76, by which, subject to exceptions provided in the ensuing sections, opinion evidence is generally declared inadmissible. 28 The purpose of s 78 is, in my view, limited. The section must be read in the light of s 56, by virtue of which evidence that is relevant in a proceeding is admissible and evidence that is not relevant is inadmissible. The focus of s 78 is (relevant) evidence of "a matter or event" as perceived by "a person" (the witness). Where (but only where): (i) evidence of that person's opinion is necessary to obtain an adequate account or understanding of his or her perception of that matter or event; and (ii) the opinion is based on what he or she saw, heard or otherwise perceived about the matter or event; then evidence of the opinion is admissible: 29 S 78 has no application unless: (i) there is a "matter or event" relevant to the proceeding; (ii) the matter or event is perceived by the witness; (iii) the witness has formed an opinion based on what he or she saw, heard or otherwise perceived about the matter or event; and (iv) evidence of the opinion is necessary to obtain an adequate account or understanding of the witness's perception of the matter or event. 30 Put another way, if a witness's "perception of a matter or event" is relevant, evidence of that perception is admissible; and if evidence of that person's opinion is necessary to obtain an adequate account or understanding of his or her perception, then an opinion based on what that person saw, heard or otherwise perceived about the matter or event is admissible as exception to the opinion rule. 31 Necessarily implicit in the section is the requirement that evidence of the witness's "perception of a matter or event" be admissible; to be admissible it must, inter alia, be relevant (s56); if, in order to obtain an adequate account or understanding of the witness's perception of the matter or event, evidence of the witness's opinion is necessary; and if that opinion is based on the witness's visual, aural or other perception: then the opinion rule does not operate to exclude evidence of the opinion. The starting point is identification of the "matter or event" which must be relevant to the proceeding. The questions are:- (i) what is the "matter or event" relevant to the proceeding? (ii) has the witness seen, heard or otherwise perceived something about the "matter or event"? (iii) has the witness formed an opinion based on what he/she saw, heard or otherwise perceived about the matter or event? (iv) is evidence of that opinion necessary to obtain an adequate account or understanding of the witness's perception of "the matter or event"? 32 Only if questions (ii), (iii) and (iv) are all answered affirmatively does the opinion rule not operate to exclude the evidence of opinion. 33 Put more simply, s 78 is designed to permit evidence of opinion that would facilitate the understanding of evidence otherwise relevant and admissible. The section assumes that the matter or event as perceived by the witness is relevant to the proceeding. That is the primary evidence. The opinion evidence is admissible as incidental to an understanding of the primary evidence. 34 Translating those observations to the present question, the relevant matter was the identity of the speakers on the DAT tapes. Mr Fung's perception of that matter did not become relevant until he had formed his opinion as to that identity. Evidence of his opinion was therefore not necessary to obtain an adequate account or understanding of his perception. It was his opinion evidence that was said to render his perception of the matter or event relevant and admissible. Without his opinion, there was no "matter or event" perceived by him, understanding of which would be facilitated by evidence of his opinion. His opinion was the primary, not the incidental, evidence. 35 I am therefore of the opinion that s 78 did not render the evidence admissible. 36 However, that does not necessarily mean that it was wrongly admitted. Notwithstanding the judge's view that, if the evidence were admissible, it was by reason of s 78, and notwithstanding the Crown's concession at trial that Mr Fung did not have specialised knowledge based on his training, study or experience, another alternative is available. A further exception to the opinion rule is provided by s 79 which is in the following terms: "If a person has specialised knowledge based on the person's training, study or experience, the opinion rule does not apply to evidence of an opinion of that person that is wholly or substantially based on that knowledge." 37 On appeal the Crown argued that Mr Fung's opinion was admissible under this section. While it was conceded that Mr Fung lacked formal qualifications derived from a specialised course of training or study, which would ordinarily be regarded as the foundation for the admission of opinion evidence under this section, it was contended that he fell into the category of "ad hoc expert" recognised in R v Menzies [1982] 1 NZLR 40; R v Butera (1987) 164 CLR 180; R v Eastman (1997) 158 ALR 107; R v Cassar and Sleiman, unreported, [1999] NSWSC 436, unreported. 38 The notion of an "ad hoc expert" appears to have originated in Menzies. The ad hoc expertise in that case was the capacity to decipher tape recordings that were substantially unintelligible to anybody who had not played them repeatedly. A transcript of tape recordings made by a police officer who had, by listening to the tapes many times, acquired such expertise, was held to have been properly put before the jury. The following passage appears in the joint judgment of Cooke , McMullin, Summers JJ and Sir Clifford Richmond: "If the tape is reasonably short and clearly audible there can normally be no justification for allowing a transcript as well as playing the tape. But there will be cases in which the aid of an expert is reasonably necessary. For example, there may be the use of a foreign language. Or deficiencies in the recording may make it necessary to play tapes more than once to enable a better understanding, yet the sheer length of the tapes may mean that inordinate time would be taken by replaying them to the jury. In such cases, while there should normally be at least one playing to the jury, the evidence of an expert should be admissible as an aid to the jury. He may be a temporary expert in the sense that by repeated listening to the tapes he has qualified himself ad hoc and we see no compelling reason why his evidence should not take the form of production of a transcript which can be admitted as an exhibit. Whether the judge allows the jury to have copies of the transcript, as distinct from merely hearing it read, must be a matter for his discretion in the particular case, bearing in mind the requirements of justice and any risk of unfairness to the accused." (emphasis added) 39 The idea of the ad hoc expert was endorsed by the High Court in Butera. Again, tape recordings were involved. This time the conversations recorded were mainly in the Punjabi language, with some Thai, Malay and English. Parts of the recordings were indistinct and could only be made out after being listened to repeatedly by a person familiar with the languages. Transcripts of the translation made after that exercise had been undertaken were held to have been rightly admitted. In the course of so deciding Mason CJ, Brennan and Deane JJ quoted the passage from Menzies extracted above, and accepted the concept of the ad hoc expert. 40 Both Menzies and Butera were cases decided in the context of jurisdictions in which the rules of evidence were other than those contained in the Evidence Act applicable to the present case. It is for that reason that Eastman and Cassar are important. Eastman was an appeal from a conviction in the Australian Capital Territory, under rules of evidence relevantly identical to those presently applicable, contained in the Evidence Act 1995 (Cth). Cassar was a decision under NSW law and was governed by the same provisions as govern the present appeal. There have, accordingly, been two decisions to the effect that the concept of the ad hoc expert developed under different evidentiary regimes continues to have application under the current NSW evidentiary regime. For myself, I believe s 79 is sufficiently wide to accommodate the idea of an ad hoc expert. 41 The question which next arises is whether it has been shown that Mr Fung was such an expert. This is a matter of some complexity. There is no question that he was an expert for the purpose of the interpretation of the DAT tapes. The question is whether his comparison of the two sets of tape recordings qualified him as an expert for the purpose of identifying two of the three voices he distinguished on the DAT tapes as those of the two appellants, after hearing their voices on the police tape. 42 To characterise this as a simple voice comparison exercise would be to over simplify the exercise Mr Fung undertook. As he said, he listened to the pitch and modulation of the voices, but he also took into account the use of language, accent, and the speed of speech. In the process of translating the DAT tapes he had listened to the voices many times and had, no doubt, acquired (even unconsciously) a familiarity with the voices on those tapes, their accents and speech patterns. On the other hand, the basis he had for comparison was very limited. One criticism, which has some merit, was that the recording of the police conversation with Wong was, except when Wong stated his name in Cantonese, all in English. In relation to Wong, therefore, Mr Fung was comparing a voice speaking in Cantonese on the DAT tapes with a voice speaking in English in the police tapes. In Leung's case most of the conversations on the police tapes were had with the assistance of one of the police interpreters and, in so far as Mr Fung heard Leung speak, he was comparing two recordings in the same language, but, as was pointed out in the cross-examination on the voir dire, in very different circumstances. Further, Mr Fung placed some emphasis on the relative volume of speech, but conceded that he was unaware of the location of the speakers relative to the transmitting device in the garage conversation, or the tape recorder in the police tapes. There were therefore, some deficiencies in Mr Fung's capacity to reach a view about the identification of the voices. 43 The line between opinion evidence and evidence of fact is not always clearly defined. Evidence of physical identification illustrates the point. On the one hand such evidence may be characterised as evidence of fact; but, depending on the circumstances, it may more properly be characterised as evidence of opinion. The ordinary observer would regard evidence given by a man identifying his wife of thirty years as evidence of fact; but a witness who identifies a suspect in a police lineup would be perceived as giving evidence more closely allied to opinion evidence. Where the evidence is more properly seen as opinion evidence, it is frequently opinion evidence permitted to be given by a person without specialist qualifications, but whose specialised experience of the person of whom the identification is made qualifies him or her to give the evidence. It may be that this is a familiar example of an ad hoc expert. 44 Voice comparison is not necessarily a question for expert evidence, although it may be. If the two sets of tape recordings in the present case had been in English, it would have been open to the Crown to have left it to the jury to make their own comparison and assessment of whether the voices on the DAT tapes (or any of them) corresponded to either of the voices on the police tapes. That course theoretically remained open but would have left the jury with a task immeasurably more difficult, given the reasonable assumption that no member of the jury understood either of the Chinese languages involved. The jury would, truly, have been comparing voices only, without the intrusion of language and speech patterns that are part of voice identification. 45 There is another aspect to the task undertaken by Mr Fung that should be mentioned. He was not asked to compare the voices until a few days before the commencement of the trial. There was no specific evidence as to the instruction he was given, but it is an obvious inference that he would have approached his task on the assumption that the two voices on the police tapes were in fact the same as two of the voices on the DAT tapes, and that his role was to determine which voice on the police tapes corresponded to voices identified as M1, M2 or M3 on the DAT tapes. This is a quite different task to determining whether either of the voices so corresponded. If there were any real basis to doubt the assumption, the manner in which Mr Fung was asked to perform the comparison might raise real questions of propriety. The situation is analogous to physical identification by photographs or by a police lineup, in which care must be taken not to suggest that a particular person is the suspect. However, for reasons which will appear below, I am satisfied that in this case the assumption was a valid one. It was therefore proper for Mr Fung to approach his task on the basis that two of the voices on the DAT tapes did in fact correspond to the two voices on the police tapes, and his function was to determine which was which. 46 This means that the ad hoc expertise that he brought to bear was very much more limited than it would have been had the circumstances been different. As I have noted above, Mr Fung had, during the course of translation of the DAT tapes, become familiar with the three voices. It was a relatively small step then to assign parts of the conversation to each of the two appellants. 47 For this limited purpose, I have come to the conclusion that Mr Fung was brought within the category of ad hoc expert. He was familiar with the voices on the DAT tapes from his translation; he was familiar with the accents and use of language of the participants; and he was familiar with the languages in which they spoke, sufficient to enable him to bring a greater understanding to the voice comparison than a person without that language skill would have been. It was for the jury to evaluate such deficiencies as existed and to determine whether they accepted Mr Fung's opinions. It may be assumed that those deficiencies were brought home to them with some force in Counsel's addresses. 48 I am, therefore, satisfied that the evidence was correctly admitted, and that these grounds of appeal fail. 49 Even if that were not so, I would be satisfied that the proviso to s 6 of the Criminal Appeal Act 1912 ought be applied. The evidence that the two appellants, and Law, were the only three people in the premises at the time the tape recordings were made was overwhelming. I say this notwithstanding Wong's evidence that two or three other people had been present. There was no support for that assertion. The evidence of police surveillance was extensive, and although there was no direct evidence from any police officer that the garage door was under observation at all times, there was video evidence which established that nobody else left the house through the garage. That demonstrated conclusively that the three participants in the conversation were the two appellants and Law. The conversation incriminated all three participants. It was not necessary to establish which particular parts of the conversation were attributable to which participant; counsel for Leung conceded, during the hearing of the appeal, that all participants in the conversation inculpated themselves in the offence. Once, therefore, it was established that Leung was a party to the conversation, it must follow that no substantial miscarriage of justice can be shown to have occurred. Ground 3 50 The third ground of appeal concerns the direction given by the trial judge to the jury concerning Leung's failure to give evidence. The passage of which complaint is made is as follows: "It is a matter for you whether notwithstanding the evidence of Mr Wong it would have been reasonable to expect to hear from Mr Leung himself in relation to these matters, and hear also his evidence tested by the questions in cross-examination, like the other witnesses in the case, including of course Mr Wong. It is also a matter for you whether his failure to do so makes it easier for you to accept the evidence of the Crown and draw the conclusions which the Crown asks you to draw." 51 One argument advanced on behalf of Leung can be readily disposed of. He sought to rely on the evidence given by Wong which, it was contended, was evidence for all purposes and "was capable of exonerating the appellant [Leung]". It is true that when Wong gave sworn evidence in the trial it was evidence available to be used in the case for or against Leung, but while it may not directly have implicated Leung in dealing with the heroin it certainly did not exonerate him. The only real issue raised on behalf of Wong was his knowledge of what it was that he was participating in. This evidence, if accepted, was capable of exonerating Wong, but was not capable of exonerating Leung. 52 It was further contended that the direction gave the jury the impression that there was some obligation upon Leung to give sworn evidence in the circumstances of the case. The passage extracted for the ground of appeal does not fully represent the directions given. It is convenient to set out the paragraphs that precede that criticised. They are as follows: "I turn then to the case for Mr Leung. He gave no evidence. You have not heard from Mr Leung. He had a choice of adopting the course which he did, of saying nothing or getting into the witness box as Mr Wong did and the witnesses for the Crown did, and subjecting himself to cross-examination. He chose to exercise the option of giving no evidence. That was an option which the law gives to him and the fact that he exercised that option, and the way in which he did, is not to be regarded as any admission by him of his guilt of the offence charged. You are not to draw any adverse inference against him from the fact that he chose not to give evidence on oath or under affirmation and subject himself to cross-examination. And furthermore there may be reasons, good reasons, why an accused person should remain silent, even if otherwise in a position to contradict or explain evidence in the Crown's case. However, failure of an accused person to contradict or explain incriminating evidence against him when you think it would be reasonable for him to do so, and within his power to do so, may make it easier for you to accept the evidence relied upon by the Crown, and to draw the inference or conclusions which the Crown asks you to draw. Counsel for Mr Leung, Mr Wendler, relies of course on the evidence of Mr Wong to support the conclusion that whilst it explains why Mr Leung was at 11 Ivy Place on 8 November 1997, you will conclude or at least have a reasonable doubt, that he never went into the garage and did nothing at the house which might be said to concern him in any importation of heroin. And of course, according to the evidence of Mr Wong, there is no indication that he would have any knowledge of any such importation of prohibited drugs. Again if you are of the view at the end of your deliberations that there is a reasonable possibility that Mr Wong's evidence in these respects is accurate you should acquit Mr Leung, because as I said Mr Leung is entitled to rely on Mr Wong's evidence, it being evidence generally in the case. The Crown, of course, relies on Mr Fung's evidence as supportive of its case, and it also relies on the video tape indicating the appearance of the person in the light coloured shorts, with what the Crown says is banded tattoo on the right arm, comparable, says the Crown, with the tattoo shown on the photograph Ex 23, or part of Ex 23 of Mr Leung. And of course the Crown also relies on the mobile phone." 53 The passage of which complaint is made follows immediately upon these paragraphs. 54 S 20(2) of the Evidence Act now authorises comments by a trial judge on a failure by an accused person charged with an indictable offence to give evidence. The section contains qualifications on the nature of the comment which are not contended to have been contravened by his Honour's directions. 55 The argument advanced was that the instructions quoted in the ground of appeal: "created an impermissible adverse inference against the appellant and unfairly dispossessed him of a reasonable chance of acquittal". Reliance was placed on the decision of the High Court in Weissensteiner v R (1993) 178 CLR 217. 56 Weissensteiner was decided by the High Court in relation to a jurisdiction where comment on the failure of an accused person to give evidence was not prohibited. The Court observed that failure of an accused to give evidence is not of itself evidence and is not an admission of guilt by conduct. But the Court also observed: "It is only when the failure of the accused to give evidence is a circumstance which may bear upon the probative value of the evidence which has been given and which the jury is required to consider, that they may take it into account, and they may take it into account only for the purpose of evaluating that evidence." (p 229) 57 The Court went on (p 230) to refer to evidence that could have been explained by the accused in that case. 58 Notwithstanding Weissensteiner, in R v O G D (1997) 98 A Crim R 151 Gleeson CJ, with whom Grove and Sperling JJ agreed, cautioned against the application of the principle in Jones v Dunkel (1959) 101 CLR 298 in criminal cases. His Honour said that there may be explanations for the failure to give evidence apparent to counsel that are not apparent to the judge, and that giving such a direction may cause unfairness to the accused. 59 Recognising that, in the light of s 20, there is no general prohibition on comment on the failure of an accused person to give evidence, Gleeson CJ propounded three general principles that apply to the nature and content of such a comment. The first principle is that failure to give evidence cannot be treated as an admission by conduct of guilt. Judge Davidson directed the jury plainly in these terms more than once. The second general principle propounded by Gleeson CJ is that it is commonly appropriate to instruct a jury that failure to contradict or explain incriminating evidence, in circumstances where it would be reasonable to expect it to be in the power of an accused to do so, may make it easier to accept, or draw inferences from, evidence relied upon by the Crown. Judge Davidson directed the jury in precisely those terms. Gleeson CJ's third general principle is that there may be reasons, unknown to the jury, why an accused person otherwise in a position to contradict or explain Crown evidence does not do so. This direction, also, was given by Judge Davidson in precise terms. 60 Judge Davidson's directions therefore wholly complied with the principles stated in O G D. 61 Following the approach taken in Weissensteiner it is appropriate to analyse what evidence otherwise in the case Leung might have answered by giving evidence. The Crown evidence that he was present in the house while the pedestals were being smashed was overwhelming. Even so, it was strengthened when Wong gave his evidence. There was evidence, referred to in the passage from the summing-up extracted, from which the jury might have concluded that Leung was present in the garage. This was so, notwithstanding Wong's evidence that he did not see Leung in that part of the premises. There was the evidence of Mr Fung which, if left uncontradicted, placed Leung in the garage, participating in the incriminatory conversation. Absent evidence from Leung denying that the voice on the tape recording was his, the jury had little alternative other than to accept that evidence, even bearing in mind the possible weaknesses I have already mentioned. 62 Finally, and most importantly, Leung was the only person who could have given direct evidence of his knowledge, or lack of knowledge, of the activity in the garage. In my opinion it was not inappropriate for the trial judge to draw the attention of the jury, as he did, to the absence of Leung from the witness box. His Honour did that while at the same time applying the necessary caution and the appropriate safeguards. In my opinion this ground of appeal also fails. The Wong Appeal 63 As I have noted above, Wong sought to rely upon the grounds of appeal advanced on behalf of Leung. Plainly, since he gave sworn evidence, the direction complained of in Leung's Ground 3 can have no application. 64 In the light of the evidence given by Wong, he may have had some room to argue that the Crown had failed otherwise to establish his presence in the garage for a period sufficient to encompass the period over which the DAT tapes were recorded. However, he did confirm that he had been in the garage, at least for the time that it took to cover the window with the cardboard, and for the cleaning-up operation at which he assisted. That evidence was not capable of being a complete substitute for that of Mr Fung, but it did have a deal of overlap. Mr Fung's evidence against Wong was of some significance, and the grounds of appeal related to it, if made good, would also have impacted on Wong's conviction. However, for the reasons I have given above, the grounds are not made good. 65 In my opinion both appeals against conviction should be dismissed. ********* SPERLING J: 66 I have read in draft the judgment of Simpson J relating to the appeals against conviction by the appellants in this matter. I agree with the orders proposed by her. Leung 67 As to Grounds 1 and 2, I agree that the evidence was admissible and properly admitted pursuant to s 79 of the Evidence Act 1995 for the reasons given by Simpson J. I also agree with what she has said about the application of the proviso. I would prefer to reserve my position as to the scope and effect of s 78 in relation to voice identification and voice comparison evidence. 68 I agree that Ground 3 fails for the reasons given by Simpson J. Wong 69 I agree that this appeal fails for the reasons given by Simpson J. ********** 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.