Tran & Chang v The Queen [2016] VSCA 79

CRIMINAL LAW - Sentence - Application for leave to appeal against sentence - Applicant Chang convicted of trafficking large commercial quantity of drug of dependence and dealing with proceeds of crime - 13,890.7 grams methylamphetamine - Total effective sentence of 15 years' imprisonment with 12 year non-parole period - No significant mitigating factors - Application refused

CRIMINAL LAW - Sentence - Application for leave to appeal against sentence - Applicant Tran convicted of trafficking large commercial quantity of drug of dependence and possessing unregistered Category D firearm (non-prohibited person) - 13,890.7 grams methylamphetamine - Total effective sentence of 12 years and 3 months' imprisonment with 8 year non-parole period - Role in trafficking significant and above that of mere 'mule' - Parity - Lesser role compared with co-offender Chang adequately reflected in sentence -Application refused

1 The applicants, Giang Truong Tran (now aged 35) and Tony Chang (now aged 42) are brothers. In May 2015, they were each convicted, in the County Court at Melbourne, on Charge 1 of an indictment which alleged that they had, between 3 May 2013 and 26 June 2013, trafficked in a large commercial quantity of a drug of dependence (methylamphetamine). Chang was also convicted, on Charge 2, of having, on 31 May 2013, dealt with the proceeds of crime, namely a sum of $429,430 in cash. Tran was convicted, on Charge 3, of having, on 26 June 2013 (while being a non-prohibited person) been in possession of an unregistered Category D longarm that was not registered.

2 The applicants were sentenced on 10 August 2015 as follows:

Traffick large commercial quantity of methylamphetamine [Drugs, Poisons & Controlled Substances Act 1981 s 71(1)]

Life imprisonment and not more than 5000 penalty units

Possess unregistered Category D Longarm - non-prohibited person [Firearms Act 1996 s 6A(2)]

Traffick large commercial quantity of methylamphetamine [Drugs, Poisons & Controlled Substances Act 1981 s 71(1)]

Life imprisonment and not more than 5000 penalty units

Deal with proceeds of crime [Crimes Act 1958 s 194(2)]

3 Each applicant now seeks leave to appeal against both conviction and sentence.

4 As regards conviction, both applicants rely upon what are, in substance, the same grounds of appeal, which are as follows:

1. The learned trial judge erred in permitting the Australian Crime Commission ('ACC') employed translator, Ms Dep Nguyen, to give voice identification evidence.
2. The learned trial judge erred in permitting the ACC employed translator, Ms Dep Nguyen, to give evidence as a lay witness.
3. The learned judge's direction on the lay evidence of voice identification was inadequate and confusing in that her Honour:

(a) failed to properly instruct the jury in accordance with s 78, and

(b) instructed the jury in a confusing manner on identification and recognition.

5 As regards sentence, Tran relies upon the following grounds of appeal:

1. The learned sentencing judge erred in her order for cumulation.
2. The learned sentencing judge erred in failing to give sufficient weight to the principles of parity.
3. The sentence was manifestly excessive in that the learned sentencing judge gave insufficient weight to the applicant's previous good character.

6 Chang's grounds in support of his application for leave to appeal against sentence are as follows:

1. The learned sentencing judge took irrelevant considerations into account.
2. The learned sentencing judge erred in failing to give sufficient weight to the principles of parity.
3. The sentence is manifestly excessive.

7 On the evening of 26 June 2013, after a lengthy multi-organisational investigation known as Operation Stringybark, the applicants were both arrested. The investigation had targeted an organised crime syndicate engaged in the cross-border trafficking of large quantities of methylamphetamine, and facilitating the distribution of that drug in Melbourne.

8 The police had, over time, obtained a number of telephone intercept warrants allowing them to monitor several mobile telephones belonging to Chang. As it happened, most of these conversations, and the text messages sent to and from these phones, were in Vietnamese. A number of them were said to involve both Chang and Tran. Others were said to be between Chang and a man named Pham. They were translated in 2013 by Ms Dep Nguyen, a translator employed by the ACC.

9 On 31 May 2013, members of the ACC followed Chang and Pham to a billiard hall in Buckley Street, Footscray. Pham remained in his car. Chang emerged from the hall carrying a 'VB' cardboard box. Chang was seen to place the box on the front passenger seat of Pham's vehicle. Pham then drove off (without Chang), and was intercepted shortly afterwards. The box was found to contain $429,430 cash. Chang's fingerprints were subsequently located on the tape wrapped around the box. This conduct formed the basis of Charge 2 (proceeds of crime).

10 On 22 June 2013, Chang was arrested. He was found to be in possession of $1,530 in cash and two mobile telephones. One of these phones had been the subject of a telephone intercept warrant. It seems that Chang was released on that day, or shortly thereafter.

11 On 26 June 2013, a search warrant was executed at Tran's home. He was present at the time. Police found a number of garbage bags concealed in the ceiling cavity of the house. These contained 28 taped and vacuum sealed parcels weighing approximately 500 grams each. In total, 13,890.7 grams of methylamphetamine, of between 78.6 and 79.9 per cent purity, were seized. The seizure of these drugs formed the basis of Charge 1, trafficking on a Giretti[1] basis a large commercial quantity of methylamphetamine.

12 Also seized during the search of Tran's home was $31,850 cash, together with several mobile telephones, some of which had been the subject of telephone intercepts. Police located, in close proximity to the drugs, an M1 carbine semi-automatic centre fire rifle in the ceiling (Charge 3). They also found in the ceiling a number of plastic snap-lock bags.

13 It is important to note that in a text message dated 17 June 2013, the question was asked, as translated, 'where did you put that 1?' Translated, a text in reply said, 'where is the film kept my friend wants to watch'. These texts were followed by a telephone conversation half an hour or so later, which was translated as follows:

Male 1: Hello.

Male 2: Yeah.

Male 1: Well, where are the films kept?

Male 2: Get the whole set or the singles?

Male 1: Get uh uh the whole set.

Male 2: Ah in the ceiling.

Male 1: Huh?

Male 2: In the ceiling ... below the heater. Get a ladder to be up there. Right at the heater where we stand. Underneath the timber. It is hollow underneath. It is the house heater. In the ceiling.

Male 1: All right.

14 Moments later, there was a text message translated as, '[n]ext to the heater there is a piece of timber of about 1 metre it is under there.'

15 This text was in turn followed by a telephone conversation between two men, during the course of which there was discussion about the precise location, in the ceiling, of the 'films'.

16 Then, on 20 June 2013, by text, one of the parties said to the other, 'put out 6 rolls of film tomorrow the younger brother is coming up to pick up to watch'.

17 The Crown case was that these exchanges were carried out in code, with 'film' being used as a reference to drugs. According to the prosecution, the various exchanges were between Chang and Tran. This was said to be confirmed by the fact that the drugs were found in the ceiling of Tran's home at precisely the location that had been described in the course of those conversations.

18 Essentially, the Crown case was that Chang was the controller of the entire drug syndicate. It was said that he acted as the conduit between the international suppliers, and those who would sell the drugs in this country. Tran was said to have played a lesser, but still important, role. In particular, it was said that he was responsible for looking after the drugs so that they could be on-sold in accordance with Chang's instructions. In that sense, Tran was said to be more heavily involved than what could be classed as a mere courier.

19 In addition to the telephone intercepts, the prosecution relied upon a substantial body of circumstantial evidence to establish its case. This included detailed surveillance evidence of the two men over a period of some weeks. However, it is fair to say that the intercepts themselves were central to the allegation of Giretti trafficking.

20 An important aspect of the Crown case, therefore, involved proof that the two men recorded in the telephone intercepts were in fact Chang and Tran.

21 In part, the jury were invited to draw that inference simply as a matter of common sense. For example, one of the men who took part in the critical conversations was referred to as 'Tony'. It was said, on behalf of the Crown, that this was plainly a reference to Tony Chang. In addition, one of the mobile telephones that was used in these conversations was actually registered to Tran. He was found to be in possession of that telephone on the day of his arrest.

22 There was a strong circumstantial case against each accused irrespective of what could be established by way of voice identification. However, the Crown realised, somewhat belatedly, that its case would be strengthened if it could prove that the voices on the relevant recordings were those of Chang and Tran. To that end, it sought to utilise the services of the translator Ms Nguyen who had, in 2013, translated what was being said on the relevant tapes.

23 The defence case, at trial and before this Court, was simple. It was submitted that insofar as the Crown case was circumstantial, the inferences for which it contended could not be safely drawn. Moreover, it was submitted that the jury could not be satisfied, to the requisite degree, that the voices recorded were those of Chang and Tran and, accordingly, the telephone discussions were of no assistance to the prosecution.

24 Both applicants had been questioned after their arrest. Although they answered a number of questions, neither made any direct admission of having trafficked drugs. Chang, however, acknowledged that he had visited Tran at Tran's home many times in the past. It was put to him that on 17 June he had had a conversation with his brother on a mobile phone during which he asked Tran where the 'heater' was located. He was asked whether he could recall that conversation. He answered, 'I don't know'. He then asked whether he ever watched movies at his brother's house, and responded, 'no'. It was then put to him that he had asked about the location of the 'film' because a 'friend' wanted to watch it, and he again answered, 'I don't know'. It was put to him that the word 'film' was code for 'drugs' and he responded, 'no ideas'.

25 Tran was also interviewed by police on the evening of 26 June 2013. He gave a number of evasive answers, but once again did not make any direct admissions of having trafficked drugs.

26 In the trial, neither applicant called any evidence.

27 It is appropriate at this stage to say something more about Ms Nguyen. Of course, she was always going to be required to give evidence of the accuracy of her translations of the recorded conversations. She had carried out those translations over several weeks in 2013.

28 Ms Nguyen gave evidence that she was of South Vietnamese background. She said that she had been employed by the ACC since 1995 as a Vietnamese translator. She was highly qualified in that regard, having gained a Master's degree in Applied Linguistics. She had achieved the status of a Level 3 interpreter in Vietnamese.

29 Ms Nguyen described how, in 2013, in the ordinary course of her duties, she was assigned the task of listening to various telephone calls. She said that if these calls were not listened to in real time, she would attend to the recordings shortly after they were made, and translate them at that stage.

30 Ms Nguyen said that her first task in 2013 had been to prepare what she described as 'summaries' of the various conversations. At a later stage, she would prepare transcripts of the actual conversations themselves, translated from Vietnamese. She said that her ordinary practice was to look for differences in voice in order to be able to ascribe parts of the conversation to one participant or another.

31 Ms Nguyen said that it was her invariable practice to designate the first male voice that she heard in a recorded conversation as M1, and the second as M2. In practical terms, that meant that the recipient of the call, who would generally speak first, would be designated M1, and the maker of the call M2. She said that she would use exactly the same descriptors for subsequent recorded conversations, even where the participants were not the same as those recorded earlier. Accordingly, the one person might be M1 in one conversation, and M2 in another.

32 Ms Nguyen made a supplementary statement on 14 April 2015 shortly before the commencement of the trial. In that statement, she said that, at that time, she had been asked by the ACC to refresh her memory of what had been said in the recorded conversations from 2013, and see whether she could identify by voice the various speakers. To that end, she was provided with audio, but not DVD, recordings of both Chang and Tran's records of interview.

33 Ms Nguyen said that, throughout the entire period from April to June 2013, she had listened to all of the telephone intercepts recorded under the warrants relevant to this case. She added that throughout that period, her opinion was that the same person had used all of the services intercepted under the warrants. She identified Chang as that person.

34 Ms Nguyen further stated in her supplementary statement that she had based that opinion partly upon the use of the speaker's name, 'Tony', and partly upon a number of features peculiar to Tony's speech. She referred to the fact that the male speaker had a South Vietnamese accent, and that he spoke with a nasal and slightly high pitched tone. She also noted that in one of the conversations the man referred to as Tony had mentioned an address in Buckley Street, Footscray. She was conscious of the fact that this happened to be the address of the billiard hall at which Chang was seen on 31 May 2013, and which was owned and operated by another of Chang's brothers. Ms Nguyen was able to say that, based upon this combination of factors, the speaker in question was Tony Chang. She said that she had already reached that conclusion in 2013, self-evidently without ever having attempted a comparison of the recorded voice with that of Tony Chang as contained within his 2013 record of interview.

35 In essence, Ms Nguyen's evidence, both in her supplementary statement and on the voir dire, was that when she heard Chang's voice in his record of interview and compared it to the voice of the man who had taken part in the intercepted conversations in 2013 they were, in her opinion, identical. In other words, she was fortified in her view that it had been Chang's voice that she had heard in 2013 by engaging in the voice comparison that she had been asked to undertake shortly before the commencement of the trial.

36 When it came to Tran, Ms Nguyen's evidence was perceptibly different.

37 In her supplementary statement, Ms Nguyen had been prepared to say, on the basis of the totality of the evidence as she understood it to be, that Tran was the other participant in the telephone conversations with Chang.

38 When Ms Nguyen gave evidence on the voir dire, she said that she had listened to some 20 or so of the intercept calls prior to making her supplementary statement. She said that she had selected those calls herself, rather than having had someone else choose them for her. She did so solely on the basis that they ended with the numbers 0764, because she thought that the male speaking in those calls was the same voice she heard on Tran's record of interview.

39 Ultimately, the trial judge ruled that Ms Nguyen would be permitted to give voice identification evidence in accordance with her supplementary statement. That ruling is discussed from paragraph [58] below.

40 Notwithstanding what Ms Nguyen had said in her supplementary statement, her evidence before the jury took a somewhat different form. She was unable categorically to identify Tran's voice, because the voice of the man said to be Tran appeared in fewer conversations than did the voice of the man said to be Chang. In addition, Ms Nguyen said that the second voice was less 'distinctive' than that of Chang. Accordingly, in her oral evidence before the jury, she could not positively attribute that second voice to Tran. Rather, Ms Nguyen said that she could say that whoever it was that had been speaking with Chang throughout the relevant conversations, it was always one and the same person.

41 When Ms Nguyen gave evidence before the jury, she first outlined the nature of her duties between April and June 2013. The transcript then reads as follows:

[Prosecutor]: At that point in time, do you know the actual identity of either of the speakers?

[Ms Nguyen]: Yes

[Prosecutor]: At that early stage of the transcription process?

[Ms Nguyen]: This is the second stage of my translation.

[Prosecutor]: You did your summaries earlier?

[Ms Nguyen]: Yes.

[Prosecutor]: You have told us about that?

[Ms Nguyen]: Yes, I told you about that. This is the second stage of my translation task. We listen to the two voices, what I mean here is male 1 and male 2. I could recognise the voices.[2]

42 On one view of her evidence, Ms Nguyen was saying that even as far back as 2013 she had been able to recognise the voices of both Chang and Tran. Self-evidently, that would have been without recourse to their records of interview which she had not heard at that stage. Her voice 'identifications' at that point would have had to have been based, in large measure, upon inferences that she drew from the surrounding circumstances, as well as the actual content of the recorded conversations.

43 Ms Nguyen did, however, go further. For example, she described Chang's voice as 'creaky' and 'breath down'.[3] She also said that he used terms considered 'casual' in the Vietnamese language to refer to the other speaker.[4]

44 As we have earlier indicated, when it came to Tran, Ms Nguyen was less certain in her attribution when giving evidence before the jury. Whereas Chang's voice was said to be distinctive in the ways set out above, Ms Nguyen would only say that Tran's voice was 'warmer' and that he sounded more 'gentle'.[5] She noted that the man to whom Chang was speaking also appeared to take his time before answering questions put by Chang.

45 Ms Nguyen had no doubt that it was Chang's voice that could be heard in the incriminating conversations. However, as regards Tran, she did not go as far, before the jury, as she had previously been prepared to do in her supplementary statement. She would go no further than to say that Tran's voice, as recorded in his record of interview, was 'similar' to that of the second voice in the recorded conversations. She was, however, insistent that although she could not positively identify Tran's voice from her comparison of the recorded conversations and his record of interview, the man speaking to Chang was always the same person.

46 It is plain from the prosecutor's closing address that he understood full well the distinction that Ms Nguyen had drawn between positively identifying Chang's voice, and her description of the second voice as being similar to that of Tran.

47 Nonetheless, that second speaker had clearly taken part in a number of highly incriminating conversations with Chang. Accordingly, so the prosecutor submitted, any evidence that tended to identify Tran as a participant in any one of those conversations (including, for example, the important conversation of 17 June 2013) would have the effect of identifying him as the second speaker in all of the relevant conversations.

48 The trial judge, in her charge to the jury, also understood Ms Nguyen's evidence in this way. She distinguished between Ms Nguyen's confident assertion going back to 2013 that the main speaker in the recorded conversations had been Chang, and her unwillingness to go that far in relation to Tran. Indeed, the trial judge said, quite accurately:

Now the final stage of her work, that is attributing a specific individual to the voice on comparing the record of interview of the accused. She attributed the voice of Tony, as referred to in the call to the taxi, you might recall that being one of the calls in the collection that you have, as that of Tony Chang, on listening to his record of interview. She did not attribute the voice of Tran on listening to the record of interview, to any of the calls that she heard.[6]

49 In effect, therefore, the trial judge treated Ms Nguyen's voice attribution evidence regarding Tran, as quite separate from, and weaker than, her evidence regarding Chang. Neither side at trial took exception to that overall characterisation of Ms Nguyen's evidence.

50 As attribution was plainly in issue, Ms Nguyen was cross-examined at length by Chang's counsel regarding that matter. She said that she had previously given evidence of 'voice recognition' on some five to 10 occasions. She acknowledged that some two years or so had elapsed from the time that she had first listened to the intercept tapes to the time at which she had refreshed her memory by listening to a number of them in the days leading up to the trial. She said that she had been provided with the audio of Chang's record of interview, but not the DVD. She could not recall specifically which of the tapes she had played for the purpose of the attribution exercise.

51 It was suggested to Ms Nguyen that there were a number of differences between what she had said in both her supplementary statement and on the voir dire, and in her evidence before the jury. It was put to her that her evidence regarding voice attribution could not be relied upon. That was denied.

52 Although it was never put specifically to Ms Nguyen in cross-examination, it was suggested implicitly in closing argument on behalf of Tran that her attribution evidence was tainted because she knew whose police interview she was listening to before undertaking the attribution task. In any event, counsel for Tran further submitted in his closing address, Ms Nguyen was unable to say that it was the same person speaking in the calls and Tran's interview.

53 From the outset of the trial, defence counsel for both accused objected to Ms Nguyen being permitted to give what was variously described as 'voice identification' or 'voice recognition' evidence.

54 Initially, the prosecution sought to justify the reception of Ms Nguyen's attribution evidence by relying upon s 79 of the Evidence Act 2008 (Vic) ('the Act') (the 'specialised knowledge' exception to the opinion rule). It was submitted that Ms Nguyen was relevantly qualified, by her experience, to give evidence of that kind.

55 It seems that the prosecutor was not aware, at that stage, of the decision of this Court in Kheir v The Queen.[7] Once that case was drawn to his attention, he resiled from any reliance upon s 79. He sought instead to invoke the 'lay opinion' exception to the opinion rule contained in s 78.

56 The key provisions of the Act, therefore, so far as this particular ground of appeal against conviction is concerned, are those dealing with the reception of opinion evidence. Relevantly, in this case, they are as follows:

76 The opinion rule

Evidence of an opinion is not admissible to prove the existence of a fact about the existence of which the opinion was expressed.

...

78 Exception - lay opinions

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.

...

57 It is useful also to refer to s 79, which was the provision originally invoked but later disavowed:

79 Exception - opinions based on specialised knowledge

(1) 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.

(2) To avoid doubt, and without limiting subsection (1) -

(a) a reference in that subsection to specialised knowledge includes a reference to specialised knowledge of child development and child behaviour (including specialised knowledge of the impact of sexual abuse on children and their development and behaviour during and following the abuse); and

(b) a reference in that subsection to an opinion of a person includes, if the person has specialised knowledge of the kind referred to in paragraph (a), a reference to an opinion relating to either or both of the following -

(i) the development and behaviour of children generally;

(ii) the development and behaviour of children who have been victims of sexual offences, or offences similar to sexual offences.

The judge's ruling regarding Ms Nguyen's attribution evidence

58 As will be seen from the trial judge's ruling, relevant extracts from which are set out below, she concluded that although s 79 had no application, Ms Nguyen could give lay opinion evidence pursuant to s 78.

59 The trial judge did so, of course, on the basis that Kheir dictated that approach. However, she also did so on the basis that adequate directions would ensure that Ms Nguyen's opinion regarding attribution was not elevated to the status of that of an expert.

60 After setting out some of the central features of Ms Nguyen's evidence on the voir dire, the trial judge said:

The prosecution argued the evidence was admissible under the Evidence Act. The prosecution initially argued the evidence of this witness was opinion evidence on the basis of her study, training and experience, presumably under s 79 of the Evidence Act, Expert Opinion.

In submissions before me this morning the prosecution argued that the evidence was admissible under s 78 as a lay opinion. Reference was made to Kheir v. The Queen [2014] VSCA 200 and the analysis of both s 78 and 79 with respect to voice recognition or identification evidence. It was submitted by the prosecution that this witness, who was translating her native tongue and who had familiarity with the language and had expertise in listening to these calls, was capable of providing opinion as to attribution of the speaker in comparison with other material.

Mr Jackson argued on behalf of Mr Chang that the evidence was not admissible as the defence were not in a position to test the basis of her opinion. This was so, it was submitted, as she was unable to identify the calls on which she based that opinion. Further it was argued that even if the evidence was admissible in the exercise of discretion I should exclude the evidence as there would be unfair prejudice to the accused Chang principally because of the inability of defence to challenge the basis of the opinion.

Reliance was placed on Kheir and the difference between the evidence of voice recognition in that case and that which exists here, principally the level of familiarity established by the evidence and the certainty of the evidence founding the basis of the opinion. Neither of these it was submitted was established in this case.

Mr Patton on behalf of Mr Tran adopted the same argument. Additionally he argued that the opinion of the witness gained from her experience was only a subjective belief as referred to in the High Court in Honeysett and that the situation with respect to voice recognition in this case was akin to asking a witness to photo identify with only one photo. Further it was submitted that in the exercise of my discretion I should exclude the evidence as there was unfair prejudice in the witness describing herself as a linguist, with those qualifications and which gives the opinion unwarranted scientific foundation where it was only a subjective view.

There is some debate about whether the admissibility of this type of evidence is determined by a reference to s 78 or 79 of the Evidence Act. In Kheir the Court of Appeal considered the admissibility of evidence from a police officer who gave voice recognition evidence after hearing thousands of tapes containing an accused's voice and comparing that to the voice on the record of interview. The trial judge ruled the evidence admissible under s 79.

The court in Kheir considered the New South Wales decision in Leung and the description of voice recognition evidence as being ad hoc expert evidence and admissible under s 79. However as indicated in Kheir there is authority in this jurisdiction as compared to New South Wales that establishes that voice recognition is not to be gathered as a field of expertise about which only experts may give evidence. Adopting that approach in this case it's necessary to consider whether the evidence of this witness falls within s 78 ...

The matter of which this witness has a perception is the audio recordings of the phone intercepts in a language of her native tongue and the record of interview containing responses which are again in her native tongue. The perception was also as a consequence of her task in translating the phone intercepts as set out above and her familiarity with the material, though this had occurred almost two years before.

The witness did, however, give evidence that she refreshed her memory from some of the calls prior to listening to the record of interview. This evidence is relevant as the witness, given her familiarity with the material and the exercise she undertook in translating the material, including attributing the voices to specific unknown individuals, can provide assistance to the jury. She is clearly in a better position to carry out that exercise than them.

Whether the voices of each accused heard on the record of interview is the same as that on the phone intercept material is a fact in issue. The witness based her opinion on that comparison. The relevant fact is that this witness has listened to the calls in translating them over the period April to June 2013

and then re-listened to some of them in April 2015. If the jury is satisfied of that fact, then it is proven. I find the evidence admissible under s 78.[8]

61 The trial judge then went on to consider whether, notwithstanding the fact that Ms Nguyen's evidence was admissible under s 78 as lay opinion, it should nevertheless be excluded pursuant to either s 135 or s 137. She said:

The probative value of this evidence is high as, if accepted, it identifies both accused in what are arguably incriminating statements relating to this offending.

The prejudice relied upon by both accused can be summarised as follows: in respect of Chang, the witness was unable to identify the calls that she listened to to refresh her memory. In that circumstance, it was impossible for the defence to properly challenge her opinion.

The late notice by the prosecution of the evidence: in respect of Tran, the manner in which the voice recognition exercise took place was akin to a person identifying a face from one photo as opposed to many. The qualification of the witness as a linguist, as well as a translator, would have the effect of the jury treating the witness like an expert when she was not.

The use by the witness of Tran's record of interview in circumstances where the prosecution and defence had agreed that the record of interview would not be led: the prosecution submitted that each of these matters could be dealt with by appropriate directions. In respect of each of these matters, the process by which the witness formed the opinion that she did, including her level of familiarity with the material, the time gap between doing this exercise and her translation, uncertainty as to the exact number of calls she listened to to make the comparison can all be explored in crossexamination with the witness.

I have some sympathy with the late notice argument. However, it is clear from the prosecution opening that there is other evidence where it is open for the jury to infer the identity of the callers. It is not the situation that the prosecution case has substantially changed.

The argument that the process was akin to providing one photo to identify the voice fails to recognise that the witness had spent in April to June 2013 and April 15 considerable time distinguishing and then identifying the voice with the use of terms 'unknown male l' or '2' the speakers of the words that were recorded. At the time she did that exercise, the names of the speakers were not known. Any questions of suggestion or bias as to her opinion regarding the voice recognition can be explored in crossexamination.

Issues regarding the record of interview are a matter for counsel to consider and it is clear that directions can be given in accordance with the proper use of that material.

Finally, the fear that the witness would be treated as an expert: the Crown is not leading this evidence from her as an expert opinion; rather, a lay opinion. I will ensure in directions that the evidence is not treated or considered to have more authoritative weight than that of a layperson.

No doubt where evidence of this type is led, very strong directions regarding voice recognition or identification will be given to the jury and that is the way I propose to deal with the evidence.[9]

The judge's charge regarding Ms Nguyen's evidence

62 In her charge to the jury, the judge dealt with the special position of experts, and their ability to give evidence of opinion, in the following terms:

There is one other portion of the evidence relevant to this category and that's the evidence of Ms Nguyen and I will deal with that in a moment. Ordinarily, witnesses aren't allowed to give their opinions in court. They confine their evidence to their own observations. This is because it is you who are the judges of the facts and so usually it's only your opinion that is relevant.

However, the law says that people with specialised knowledge or training are allowed to give their opinions about matters within their field of expertise, if that may assist [in your] in determining your decision.

...

Now, I want to give you some directions regarding the other opinion evidence, or expert evidence, and that is the evidence of Ms Nguyen. She gave evidence of her work and opinion in respect of the material contained in the [telephone intercept] material. Recall that she told you that her work was done in different stages.

First, she listened to the [telephone intercepts] as the calls were happening and the SMSs were sent. She did that as they were going on, at that time, or in real time, I think, as was described. And also when she returned to work the following morning. She provided a summary to investigators of the content of that material.

Second, she was directed to translate some of the SMS messages and phone calls, the subject of the [telephone intercept] material. And this resulted in the transcripts that you have in your Jury Book 2. In respect of both of those two tasks, those first two tasks, they were undertaken by her in April to June 2013.

Now, the final stage of her work was in respect of some of the [telephone intercept] material and that occurred in April of this year, 2015. She was required to compare the voices of each of the accused on their records of interview, with some of the material in the [telephone intercepts], which she had previously translated and she gave you an opinion in respect of that.

Now, in respect of the first two parts of the exercise that she undertook, her evidence can be treated like that of other experts. She was called as an expert in the translation of the Vietnamese language. Her expertise in the field was not challenged. However, it was argued that there were limitations on her translations, given the manner in which she did that task. That i[s], it was not a straight word for word exercise, rather she took into account the context and nuances of the Vietnamese language. It is a matter for you whether you accept the translations as provided by her.

As part of this second part of the task, that is when she was doing the transcriptions, she was required to distinguish between the voices that could be heard. And you will recall her evidence regarding the attribution of individuals to the voices. So she had 'Male 1', 'Male 2', 'Unknown male', terms throughout that material.

Now this was part of her expertise in translating, that is, being able to distinguish voices and attribute voices to conversations in material with which she was familiar. And you will recall her evidence regarding the same male as '392', or 'bacsi', that is B-a-c-s-i. Again, it is a matter for you whether you accept the attributions that she gave, based on listening to the [telephone intercept] material.

Now the final stage of her work, that is attributing a specific individual to the voice on comparing the record of interview of the accused. She attributed the voice of Tony, as referred to in the call to the taxi, you might recall that being one of the calls in the collection that you have, as that of Tony Chang, on listening to his record of interview. She did not attribute the voice of Tran on listening to the record of interview, to any of the calls that she heard.

Ordinarily she would not have been able to give that evidence relating to voice recognition, but she could because of her familiarity with the voices, having done the exercise that she did.

As I have told you, witnesses are not usually allowed to give their opinions in court. They must usually confine their evidence to their own observations, and that is because it is you who are the judges of fact and usually only your opinion that is relevant.

So you must, in this last aspect of her evidence, remember that it is only her opinion and you are not bound by it. Like any other evidence, you can accept or reject it. You are able to do that by comparing the voices, if that is something that you choose to do. It really is a matter for you.

She was able to give the evidence because she had a broader experience with the calls than you did. She heard a lot more of the calls than you have got. So if I, in the course of the charge, talk about her opinion, when I describe someone's - sorry, if in the course of the charge I talk about her opinion, or if I describe someone's voice is said to be that of Mr Chang or the other male, as [sic] same as call 392. I am only giving her opinion evidence in that regard, the description that she gives and it is up to you whether you accept or reject that description.

However, you should keep in mind the fact that the voice identification or recognition evidence is really again just one piece of circumstantial evidence and must be considered in light of all of the other evidence in the case. I refer back again to the direction I gave you regarding reasonable inferences.

It is very important though, that you understand certain matters in respect of voice recognition evidence. There are two aspects to the identification evidence or voice recognition evidence that I want to give you some directions about.

The first is the voice identification of Chang and the other male, as same as call 392, or bacsi on those calls that you listened to. That is what this relates to, and I am pretty sure I have made that clear from the bit that I just directed you about.

The prosecution says you should accept Ms Nguyen's evidence that the voices she attributes to Tony and the other man, are the voices of Tony Chang and the other man. Now it is for you to determine whether the voices, as set out by Ms Nguyen is the voice of Tony Chang and of the same person in call 392, but I give you this warning. The experience of the law has shown that the task of voice identification must be performed with great care. That is because it can be very difficult to make an accurate identification of voices. There may be problems in clearly hearing the voices, particularly if the recordings are of poor quality or, as in this case, some of them are of very short length.

Consider the level of familiarity with voices that she had at the time that she made the voice recognition. There was a considerable time difference of two years between when Ms Nguyen was working intensively with the material, and her attribution of unknown individuals to when she compared that to the voices in the record of interview.

In addition, the relevant people may have been talking in very different circumstances and at different times, about various matters, using different words and tones of voice. It can make it difficult to ensure that any identification comparison evidence or voice recognition evidence is accurate.

It is important that you undertake or treat the evidence of the comparison of voices with special care and you should be especially cautious before relying on Ms Nguyen's evidence in relation to that comparison.

Having given you that general warning about the dangers or difficulties with voice comparison, I want to then look at specific factors that might affect the reliability of such evidence and there are two main factors that you must examine when making a comparison. (1) The quality of the material and (2) The nature of the voices to be compared. You should consider these factors carefully along with any other relevant factors when making a comparison.

As to quality, was there clarity in the voices that she compared; were there similarities in the circumstances of the recordings, that is, listening on the [telephone intercept] material and comparing the material within the [telephone intercepts], but also then comparing the [telephone intercept] material with the material in the record of interview or the police interview.

You will recall that Ms Nguyen was comparing voices that she heard on tapes, mostly in a foreign language. She was comparing that to voices that she heard of particular accused speaking to police officers during the course of [the] investigation. Was there really enough material for her to make a comparison with the record of interview? You could consider the quality of the recording. How good was the quality and quantity of content in the calls when you were comparing the voice to voice that she heard in the interview?

Counsel in their addresses pointed out a number of factors that they submitted were also relevant to the voice identification issue. Ms Nguyen was limited in her experience in comparing voices as she was required to do in this instance.

She did this task well after, I should indicate that these relate to her comparison between the [telephone intercepts] and the record of interview as opposed to the [telephone intercepts] themselves. She did this task well after she was acquainted with the voices during her work in 2013 and she had heard many other voices during her translation tasks in the two years in between. She couldn't remember the calls that she used to compare with the record of interview, though she said that there were about 20 out of the 37. Some of the calls were very short, only being one or two words.

In the record of interview itself, some of the responses were similarly just as short. There were instances where she didn't identify Mr Chang as the speaker, when the prosecution has said that it was him. That's in relation to calls 467, 468, 473 and 475.

Similar arguments were presented on behalf of Mr Tran in respect of the recognition evidence. These focus more so though, on the exercise of comparing within the telephone intercept material itself, given that she indicated that she did not identify Tran through the record of interview.

The other aspect you should consider is the nature of the voices. That is, the nature of the voices you are comparing. Are the voices particularly distinctive? Were similar words used? Was there a similar manner of speaking throughout? Are you relying too heavily on the fact that both the voices spoke with a foreign accent, or in this instance, of course, a foreign language. It can be very difficult to distinguish between two unfamiliar voices that speak in a similar language.

You will recall the evidence regarding her differences in the description of voice, and also the criticisms made. You will recall her evidence that she added some of the characteristics that she had previously identified in respect of Mr Chang's voice only in her evidence, and on previous occasions, she hadn't attributed it to being - I think the word was squeaky or creaky - it's one of the other, but I think that she did indicate that.

In respect of Mr Tran there was nothing, no particular characteristic that helped her identify the voice, rather it was possible for her to be able to distinguish the voice from the other as opposed to any specific characteristic in respect of Mr Tran.

Look at the way the people spoke to the police and whether that would be in a different kind of way in which you'd speak to someone on a phone in a normal conversation. People speak differently on the phone to the way they'd do in more formal circumstances you would think, like when they're talking to a police officer.

Consider the issue of whether, because it's in a foreign language - that is, Vietnamese - that the comparison exercise is much more difficult. All of these things are factors that you need to consider in determining whether or not you accept this aspect of Ms Nguyen's evidence.

As I say, the experience of the law is such that you need to take special care with voice recognition evidence because people can be quite honest and quite convinced they're right, but they're quite wrong.

So bear in mind those factors when you come to look at the voice recognition evidence. However, as I have indicated in respect of a number of pieces of evidence, you should keep in mind the fact that this recognition evidence again is just a piece of circumstantial evidence, and it should be considered in light of the other evidence in this case.[10]

The submissions on behalf of Chang - Conviction

63 It was submitted in support of ground 1 that Ms Nguyen ought not to have been permitted to give the attribution evidence that she did. It was said that her evidence identifying Chang's voice on the various recordings did not fall within the lay opinion exception to the exclusionary rule contained within s 78. Nor, for that matter, did she qualify as a person with specialised knowledge within s 79.

64 When pressed by this Court as to whether senior counsel for Chang was challenging the correctness of Kheir,[11] insofar as that case held that evidence of the kind led from the police informant was lay opinion and should not be viewed as evidence of an 'ad hoc' expert, he acknowledged that he could not submit that that decision was 'plainly wrong'. Nor did he argue, as he had in his written submissions, that Kheir could be distinguished from the present case. He did, however, formally reserve his rights to submit that Kheir was wrongly decided should this matter go further.

65 Kheir was a case in which the facts were in some respects similar to those in the present matter. We will refer in detail to that case at paragraphs [99]-[102] of these reasons for judgment.

66 Senior counsel for Chang was further pressed as to whether he could point to any particular requirement of s 78 that was not met in this case. He acknowledged that he could not do so. Instead, accepting for present purposes that this Court should follow Kheir in deciding his client's application, he submitted that there had been a miscarriage of justice arising out of the admission of Ms Nguyen's attribution evidence, not so much because that evidence ought not to have been received, but rather because it would have confused the jury.

67 Of course, a submission in that form could not readily be reconciled with the precise terms of ground 1. Nor, indeed, did it fall squarely within the plain language of ground 2. Both grounds are expressed in terms of error in the trial judge's decision to permit Ms Nguyen's evidence to be led. They do not complain, as such, of any possible confusion that may have been engendered by that decision. Nonetheless, ground 3, which focuses upon the trial judge's charge, does adequately cover the point. Senior counsel, in effect, argued all three grounds together, and we will deal with them on that basis.

68 In support of his submission regarding possible confusion on the part of the jury, senior counsel for Chang argued that there was a serious risk that the jury would have misunderstood the status occupied by Ms Nguyen in relation to her evidence. In relation to matters of translation, the jury would have understood that she was an acknowledged expert in the field. They undoubtedly would have accepted her evidence, largely unchallenged as it was, as to the meaning of various words spoken during the course of the recorded conversations. However, as it happened, Ms Nguyen performed a dual role. When it came to the important issue of voice attribution, the jury may not have understood that she was nothing more than a lay person, certainly one with more than passing familiarity with the voices that she heard on the tapes, but nonetheless still only expressing lay opinion.

69 It was submitted that, in those circumstances, there was a risk that the jury might have accorded greater weight to Ms Nguyen's attribution evidence than it truly merited. It was further submitted that, given that danger, nothing short of an unmistakably clear and powerful direction to the jury, to the effect that hers was merely a lay opinion, could have sufficed to avoid a miscarriage of justice. It was submitted that no such direction had, in fact, been given.

70 In his oral submissions, senior counsel for Chang did not address any specific argument in support of the second limb of grounds 1 and 2; namely, that Ms Nguyen's evidence should have been excluded either pursuant to s 135 or s 137 of the Act.

71 Section 135, of course, relevantly provides that the court may refuse to admit evidence if its probative value is substantially outweighed by the danger that the evidence might be unfairly prejudicial to a party, or be misleading or confusing. The section creates a general discretion, applicable in civil or criminal proceedings, to exclude evidence.

72 Section 137 is not couched in the language of discretion. It provides that in a criminal proceeding the court must refuse to admit evidence adduced by the prosecutor if its probative value is outweighed by the danger of unfair prejudice to the accused.

73 Senior counsel for Chang was content to adopt, in advance, the submissions regarding these two provisions that were to be advanced on behalf of Tran.

74 As regards ground 3, which complains of the 'confusing' nature of the judge's charge regarding Ms Nguyen's evidence, senior counsel for Chang properly acknowledged that he had to overcome the significant difficulty that no exception had been taken at trial to that aspect of the trial judge's charge. He submitted, nonetheless, that the judge had failed adequately to draw to the jury's attention the sharp distinction between Ms Nguyen's status as an expert on translation and her lay opinion on attribution.

The submissions on behalf of Tran - Conviction

75 Counsel for Tran, in his written submissions, essentially repeated what had been advanced on the voir dire at trial against the admissibility of Ms Nguyen's attribution evidence. Those arguments are summarised in the extract from the trial judge's ruling that we have set out at paragraphs [60] and [61] of these reasons.

76 In oral argument, counsel for Tran focussed on the question whether Ms Nguyen's attribution evidence should have been excluded in the exercise of the general discretion under s 135 or, alternatively, the statutory balancing exercise required under s 137. Counsel for Tran did not expand on what senior counsel for Chang submitted in relation to ss 78 and 79, or ground 3.

The submissions on behalf of the Crown - Conviction

77 The Crown submitted that, having regard to the decision of this Court in Kheir,[12] neither ground 1 nor 2 had any substance.

78 It should be noted that the Crown recognised that there had been some attempt on the part of the applicants, in their written submissions, to argue that Kheir could be distinguished 'on a number of bases'. For example, it had been suggested in those written submissions that the witness in Kheir did not have the skills, qualification or experience of Ms Nguyen (and, as such, that her 'lay opinion' may actually have been based upon those skills).

79 However, the Crown submitted that Kheir could not be distinguished from the present case. The Crown referred to what it considered to be similarities between the two cases, including that in Kheir the witness had listened to approximately 1000 tapes over the space of a month, whereas in the present case Ms Nguyen had listened to the telephone intercepts every day during office hours between 17 April and the end of June 2013. The Crown also submitted that the present case could not be distinguished on the basis that the witness in Kheir was not a qualified translator. Rather, the Crown said that Ms Nguyen's voice attribution evidence was not made on the basis of any of her qualifications, but on the basis of her speaking Vietnamese and having listened to the telephone intercepts.

80 Accordingly, in some ways, Ms Nguyen's evidence could be said to be demonstrably more reliable than the evidence of the police informant which had been received in Kheir. Ms Nguyen had the advantage of being a highly qualified linguist. Moreover, unlike the police informant in Kheir, she was vastly experienced in listening to tapes of recorded conversations in Vietnamese. She had spent a good deal of time, over a number of months, listening to the recorded tapes in 2013, once for the purpose of monitoring and preparing summaries, and then again for the purpose of transcription. She had listened to some 20 or so of those tapes again in 2015, shortly before the trial commenced, and had therefore refreshed her memory as to their contents before she committed to attribution. She was, therefore, so it was said, in a particularly good position to engage in the task which she had ultimately been asked to perform.

81 As regards ground 3, the Crown submitted that there was nothing at all confusing regarding the nature of Ms Nguyen's evidence in the trial judge's charge. In particular, it was submitted that there was no risk that the jury could have conflated her status as regards the two quite separate roles that she had been asked to play. The fact that no exception had been taken to the trial judge's charge in relation to these matters should be regarded as fatal to this ground.

82 In supplementary submissions received following the hearing,[13] the Crown contended that the trial judge's charge was appropriate in circumstances where, in summary:

• the prosecutor had not submitted, in his closing address, that Ms Nguyen had recognised the voice of the second speaker in the relevant phone calls as that of Tran. Nor had he relied on Ms Nguyen having given evidence of the similarities between Tran's voice in his record of interview and the second voice in the relevant telephone calls;

• counsel for Chang had submitted to the jury in his closing address that Ms Nguyen had 'no real special expertise' in voice recognition; and

• counsel for Tran had pointed out to the jury in his closing address that Ms Nguyen had not been able to say that the voice she had heard in Tran's record of interview was the same as that of the second male speaker in the relevant telephone calls.

Analysis and conclusions regarding conviction

83 Before turning to the particular grounds of appeal, it is appropriate to make some general remarks regarding voice identification. Such evidence has, in this State, generally been regarded as admissible.

84 In a helpful paper, Justice David Hodgson[14] commented that evidence of

84 voice identification could take four[15] different forms, each of which engaged the rules of evidence in different ways. Thus, such evidence could be given:

(a) of samples of recorded voices for direct comparison by the trier of fact, in criminal trials the jury;

(b) by a non-expert that, in his or her opinion, a voice heard on a relevant occasion by that witness was the voice of a particular person;

(c) by an 'ad hoc' expert whose evidence is not based on scientific training, but on such matters as close and repeated listening to a large quantity of recorded material; or

(d) by a true expert, that is a person who has made a scientific study of the relevant area.

85 In the present case, the evidence given by Ms Nguyen was capable of being regarded as falling within either category (b) or (c).

86 Of course, the jury heard the intercepted tapes and the records of interview. Accordingly, they were in a position to engage in a direct comparison of the voices recorded. In that sense, the evidence of voice identification led in this case could be regarded as falling within category (a). In such circumstances, it is necessary for a judge to give careful directions to the jury as to those considerations which could make the comparison difficult and to give a strong warning as to the need for caution in making this kind of comparison.[16]

87 The cases suggest that there was, at one time, a disagreement at common law between the courts in New South Wales and those of Victoria as to whether the admissibility of voice identification evidence, by non-experts, should depend upon the distinctiveness of the speaker's voice or the witness's familiarity with that voice.[17]

88 In Bulejcik, several members of the High Court referred to that debate, seemingly approving the Victorian decisions on that issue. However, the issue was not definitively resolved.

89 In R v Adler[18] the New South Wales Court of Criminal Appeal held that the effect of ss 55(1) and 116 of the Evidence Act 1995 (NSW) had been to remove any threshold considerations for the reception of voice identification, and to leave the matter entirely to the discretion of the trial judge pursuant to ss 135 and 137. Of course, in the event that evidence of this kind was admitted, it would be expected that strong warnings of the kind set out in ss 116 and 165 would be given.

90 In this State, the law on this subject is as stated by this Court in Kheir.[19] As a result of that decision, Ms Nguyen's attribution evidence could only be received if it satisfied the requirements of s 78 of the Act as lay opinion.

91 Of course, any identification of this kind would have to be the subject of strong warnings pursuant to ss 116 and 165 of the Act, both of which were applicable at the time of this trial.[20]

92 The second way in which, theoretically at least, Ms Nguyen's evidence might have been admissible would be as an 'ad hoc expert' giving opinion evidence under s 79. That would be the path to admissibility in New South Wales. However, as a result of Kheir, her evidence must satisfy the requirements of s 78 rather than those of s 79 in order to meet the requisite threshold.

93 The approach adopted in Kheir has long been favoured in this State. As far back as Harris[21] it was held that a police officer could give voice identification evidence based upon his having listened extensively to a large number of tape recordings. Ormiston J, as he then was, presided over the trial. His Honour observed that voice recognition, by a person with prolonged familiarity of a particular voice, involved a field in which non-expert opinion could be received.

94 The notion that evidence of voice identification could only be given by someone who had developed what later, in New South Wales, came to be described as 'ad hoc' expertise, emerged over time. Some of the early cases dealt not so much with voice identification as such, but rather with the separate, but related, question of identifying the words spoken on an otherwise indistinct recording.[22]

95 In R v Leung,[23] the New South Wales Court of Criminal Appeal held that s 79 of the Evidence Act 1995 (NSW) was 'sufficiently wide to accommodate the idea of an ad hoc expert',[24] with the relevant witness being considered such an ad hoc expert on the facts of that case.

96 Justice Simpson expressly rejected the contention that such evidence could be received as lay opinion evidence falling within s 78.[25] Her Honour's conclusion was said to lie in the wording of s 78. As has been seen, that section requires that the person expressing the relevant opinion has based that opinion on what that person saw, heard, or otherwise perceived about a 'matter or event'. In addition, evidence of that person's opinion must be necessary to obtain an adequate account or understanding of that person's perception of the matter or event.

97 Her Honour noted that the 'relevant matter' was the identity of the speakers on the tapes. The (male) interpreter'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. Without his opinion, there was no matter or event perceived by him, understanding of which would be facilitated by evidence of his opinion.

98 None of this mattered in the end. The Court concluded that the evidence in question was admissible under s 79 since the witness possessed a particular expertise, that is 'specialised knowledge' based on training, study, or experience. In other words, the interpreter fell within s 79 by virtue of his being an 'ad hoc expert'.

99 In Kheir,[26] the reasoning in Leung was considered and rejected. The accused had been convicted of a series of offences involving violence, including armed robbery and blackmail. The case against him included telephone intercepts of calls made while the victim was being held prisoner. A police informant gave evidence identifying the accused's voice as one that he had heard during a series of intercept calls. The informant had spent approximately four weeks, in eight hour shifts, listening to over 1000 such calls. He had become familiar with the voices on the intercepts and, as a result, believed he could identify the various speakers.

100 The Court noted that the police informant had no special language or interpretation skills, and was not in a position to say anything about the content of any of the conversations. He produced no secondary material to assist the jury in comprehending what was actually recorded. Rather, he simply gave voice identification evidence based on his many hours of having listened to the intercepts in question.

101 Whereas in Leung, Simpson J approached the question of admissibility under s 79 through the prism of ad hoc expertise, Kheir held that, in this State, identity evidence, whether visual or aural, had never been treated as a matter requiring proof of expertise, whether ad hoc or otherwise.[27] Specifically in relation to voice recognition, the Court considered that '[a]uthority in this jurisdiction establishes that voice recognition is not to be regarded as a field of expertise about which only experts may give evidence'.[28]

In our view, the evidence of Sergeant Bray was more appropriately viewed as falling within s 78 than s 79. The 'matter' of which Sergeant Bray had a 'perception' was the audio recordings of the telephone intercepts, the recordings of the applicant's record of interview and a comparison of the two. His perception of that comparison met the test of relevance because he was in a better position to make that comparison than the jurors were. Whether the voice heard in the intercepts was also that in the record of interview was a fact in issue, and the comparison could rationally affect the assessment of the probability of that fact. Sergeant Bray's opinion was based upon that comparison, and his opinion - that the voices on the two tapes were the same - was necessary to shed light upon the observations he made about the voices' similarities.[29]

103 The trial judge in the present case considered that the reasoning in Kheir applied to the circumstances surrounding Ms Nguyen's attribution evidence. She therefore correctly applied s 78, rather than s 79, when considering whether that evidence should be admitted.

104 The applicants having before this Court all but conceded in oral argument that every element of s 78 had been met in this case, there can be no substance in either grounds 1 and 2, at least as to the primary basis upon which those grounds rest. Ms Nguyen's evidence was admissible as lay opinion evidence pursuant to s 78. As the Crown submitted, the decision in Kheir is dispositive of this point.

105 We reiterate that although there was an attempt in the applicants' written submissions to distinguish Kheir, that attempt was all but abandoned in oral argument. Plainly, this case fell within the Kheir principle, as the trial judge, and the prosecutor below, accepted.

106 That leaves for consideration whether, as the applicants submitted, the trial judge erred in failing to exclude Ms Nguyen's evidence pursuant to either ss 135 or 137.

107 Evidence of the kind led from Ms Nguyen has been received many times in the past. So far as we are aware, such evidence has never been excluded pursuant to the general discretion contained in s 135, namely that it would be confusing to admit it.

108 The evidence given by Ms Nguyen was clear and unambiguous. There is no reason to think that the jury, having heard that evidence, would have been confused as to the basis upon which it was led. It was entirely clear that she was accepted as an expert on matters of translation, but that her attribution evidence was not to be viewed in the same light.

109 The trial judge gave what can only be described as a balanced and perfectly fair charge regarding Ms Nguyen's evidence. As can be seen from the lengthy extract of her charge dealing with that subject set out earlier in these reasons for judgment, she repeatedly stressed that the matter of attribution involved nothing more than Ms Nguyen's opinion, and that the ultimate question was entirely one for the jury. She made it perfectly clear that whereas Ms Nguyen was an expert on matters of translation (stages 1 and 2 of the task that she had carried out, in 2013), her position was different as regards the work she did in April 2015. Although it is true that the trial judge did not use the term 'lay opinion' in describing the attribution evidence, she did speak of Ms Nguyen's expertise regarding linguistic matters, and the work done in 2013.

110 In our view, there was no realistic possibility that the jury would have conflated these two roles, and wrongly assumed that Ms Nguyen was relevantly an expert who met the requirements of s 79 for the purpose of her attribution evidence. Nor was there any occasion to exercise the power conferred by s 137 to exclude evidence the probative value of which was outweighed by the danger of unfair prejudice. There was no such danger.

111 We should add that even if this case had been approached through the prism of s 79, and the New South Wales jurisprudence on this subject, it would be strongly arguable that Ms Nguyen was relevantly an 'ad hoc' expert for the purposes of that section.

112 Importantly, as we have noted, there was a substantial body of circumstantial evidence that lent support to Ms Nguyen's opinions on matters of attribution. Either Chang and Tran in fact took part in the incriminating conversations that were intercepted, or they were the victims of an amazing series of coincidences, wrongly linking them to what was actually being said.

113 Even though Ms Nguyen could not positively identify Tran's voice based on any sort of voice comparison, the inference that the second voice was indeed that of Tran was plainly open. The reasons for this are obvious, including that:

• one of the mobile telephone numbers of the male who was the second voice was that of a telephone registered in Tran's name;

• there were a number of references in the intercepted text messages, and recorded conversations, to 'films' being concealed near a heater in the ceiling. That, of course, was precisely where the drugs were located in Tran's home; and

• there were also statements in the recorded conversations that accorded with what was known of Tran's circumstances. For example, Tran has a young child. In one of the intercepted calls the relevant speaker says that he cannot leave the house because his wife was not present and he needed to mind their child.

114 In these circumstances, grounds 1 and 2 in support of the application for leave to appeal against conviction should be rejected.

115 The trial judge foreshadowed, in her ruling permitting Ms Nguyen to give evidence of attribution, that she would ultimately give a strong direction to the jury regarding the need to exercise particular care when it came to evidence of voice identification.

116 It is hardly surprising, having regard to the thoroughness with which the trial judge approached the task of giving appropriate directions regarding the need for caution in relation to voice identification, that no exception was taken to the charge regarding that issue.

117 Defence counsel in their closing addresses highlighted the very matters that the trial judge drew to the jury's attention in warning them of the dangers of voice identification evidence. The trial judge gave the force of judicial authority to those dangers, and could not reasonably have been expected to say more regarding those matters than she did.

118 The only point now made before this Court regarding ground 3 is that the judge should have done more to make clear to the jury the distinction between Ms Nguyen's opinions regarding matters of linguistics (as to which she was, undoubtedly, an expert) and her opinions regarding voice attribution, as to which she was merely a lay witness, albeit one particularly qualified to express those opinions.

119 In our opinion, the fact that no exception was taken to this aspect of the charge confirms that there is nothing in this point. The charge regarding voice identification was, in fact, impeccable.

120 It follows that ground 3 in support of each application for leave to appeal against conviction should be rejected.

121 The only point that was pressed regarding sentence so far as Tran was concerned was one of parity. It was submitted that his role in the trafficking business was little more than that of a courier or 'mule', but that he had been sentenced effectively as a principal, not far short of Chang.

122 That submission does not sit well with the way in which Tran's plea was conducted. Before the trial judge, counsel for Tran accepted that the applicant could not strictly be classed as a mule, or a 'fetch and carry boy', yet at the same time he could not be said to be a 'director'.

123 When the trial judge responded to that submission by pointing out that Tran had been 'essential to the organisation', counsel agreed, and added that, on the basis of the jury's verdict, Tran 'did have some executive power'.[30]

124 That was both an apt and necessary concession, and one from which Tran ought not now be permitted to resile. His role in this enterprise was significant, and far greater than that of a low level player. His willingness to store this very large quantity of drugs in the ceiling of his home facilitated the commission of this offence. It demonstrated the 'executive' role that Tran played, albeit a role inferior to that of Chang. That differentiation was appropriately recognised by the difference in the sentences imposed on each applicant. There is no merit in this point, and no substance in the suggestion that this sentence was wholly outside the range reasonably available for offending of this gravity.

125 Tran's application for leave to appeal against sentence should be refused.

126 Senior counsel for Chang said little by way of oral submission in support of his client's application for leave to appeal against sentence. That was not surprising. There was not a great deal to be said in support of any of those grounds.

127 One matter that was raised by the Court during the course of argument was whether Chang's non-parole period of 12 years, which was 80 per cent of the total effective sentence of 15 years, was excessive, particularly since the ratio between the head sentence and the non-parole period was not explained by the trial judge.

128 However, having considered that matter, and what was said on this subject in Romero v The Queen,[31] it is plain that the trial judge did not fall into error in imposing the sentence that she did.

129 This was very serious offending. The quantity of drugs was substantial. The potential rewards were great. Massive harm would have been done had these drugs been distributed into the community, as was obviously the intention.

130 Chang stood his trial. There were no mitigating factors of any real significance upon which he could draw. Indeed, there was a prior conviction for trafficking which could properly be viewed as an important aggravating factor.

131 Although some might view this sentence as stern, it cannot reasonably be contended that it fell outside the range reasonably available to the sentencing judge.

132 Accordingly, Chang's application for leave to appeal against sentence should be rejected.

133 It follows that, in each application, leave to appeal against both conviction and sentence should be refused.

[1] R v Giretti (1986) 24 A Crim R 112 ('Giretti').

[2] Transcript of Proceedings, DPP v Chang & Tran, County Court of Victoria, CR-14-00327 and CR14-00329, Judge Quin, 13 April 2015, 294. ('Trial Transcript').

[4] There were also references in the recorded conversations to the term translated as 'bro'. The jury would have been entitled to regard these references as significant in the case of two men who were in fact brothers. Alternatively, of course, they might have taken the view that this term was nothing more than a colloquialism for a good friend.

[7] (2014) 43 VR 308 ('Kheir').

[8] Transcript of Proceedings, DPP v Chang & Tran, County Court of Victoria, CR-14-00327 and CR14-00329, Judge Quin, 16 April 2015, 87-90 ('Ruling').

[10] Trial Transcript 472-481 (emphasis added).

[11] (2014) 43 VR 308.

[12] (2014) 43 VR 308.

[13] Neither counsel for Chang nor Tran elected to file supplementary submissions on the question of what was said in closing addresses about the different evidence Ms Nguyen gave regarding attribution in respect of Chang compared with Tran.

[14] Justice David Hodgson, 'Speaker Identification - A Judicial Perspective' (Paper presented at the Australian Research Council Network in Human Communication Science Workshop: FSI not SCI - Perspectives in State-of-the-Art Forensic Speaker Recognition, Sydney, New South Wales, Australia, 6-7 December 2007).

[15] Justice Hodgson actually referred to a fifth type of voice identification evidence, namely expert evidence regarding the reliability of comparisons made by other persons. That category is of no present relevance so far as these applications are concerned.

[16] Bulejcik v The Queen (1996) 185 CLR 375, 397-399 (Toohey and Gaudron JJ) ('Bulejcik').

[17] R v Smith (1984) 1 NSWLR 462 ('Smith'); and R v Brownlowe (1986) 7 NSWLR 461, which represent the New South Wales position prior to the enactment of the Evidence Act 1995 (NSW), so holding. However, in R v Hentschel [1988] VicRp 46; [1988] VR 362 the Full Court of the Supreme Court of Victoria declined to follow those cases (Murphy and Brooking JJ, Hampel J dissenting). See also R v Harris (No 3) [1990] VicRp 28; [1990] VR 310, 316-7 ('Harris').

[18] [2000] NSWCCA 357; (2000) 52 NSWLR 451.

[19] (2014) 43 VR 308.

[20] Now Jury Directions Act 2015 ss 32 and 36.

[21] [1990] VicRp 28; [1990] VR 310.

[22] See, for example, R v Menzies [1982] NZCA 19; [1982] 1 NZLR 40; and Butera v DPP (Vic) [1987] HCA 58; (1987) 164 CLR 180.

[23] [1999] NSWCCA 287; (1999) 47 NSWLR 405 ('Leung').

[24] Ibid, 413 [40] (Simpson J with whom Spigelman CJ and Sperling J relevantly agreed).

[25] Spigelman CJ and Sperling J considered it unnecessary to decide the case on the basis of s 78, preferring instead to reserve their position as to the scope and effect of that section.

[26] (2014) 43 VR 308.

[27] Kheir (2014) 43 VR 308, 322 [61]-[62].

[29] Ibid 323 [65] (citations omitted).

[30] Transcript of Proceedings, DPP v Chang & Tran, County Court of Victoria, CR-14-00327 and CR14-00329, Judge Quin, 24 July 2015, 558 (Plea).

[31] [2011] VSCA 45; (2011) 32 VR 486.