Mr Justice Fok PJ: 1. The appellant was convicted, after re-trial,[1] of murdering his girlfriend. He was granted leave to appeal that conviction on the ground that it was reasonably arguable the judge presiding over his re-trial misdirected the jury in respect of the objective limb of the defence of provocation as it applied to his case. After service of the appellant’s written case, the prosecution, as respondent, indicated that it would concede the appeal on this ground and the parties were directed to file a joint written case for the consideration of the Court in accordance with the established procedure for uncontested appeals.[2] 2. The only contested part of the appeal was whether, if the appeal is allowed quashing the conviction for murder without substituting a conviction for manslaughter, the appropriate consequential order should include a direction for a further re-trial. This was addressed by the parties in separate written cases and orally at the hearing before us. At the conclusion of the hearing, the Court allowed the appeal, quashed the appellant’s conviction and ordered a re-trial. We indicated that we would hand down our reasons for doing so in due course, which we now do. The background facts leading to conviction below 3. The facts out of which the murder charge arose are fully set out in the judgment of the Court of Appeal now under appeal.[3] For present purposes, a short summary of the salient facts will suffice. 4. In 2009, the appellant (then aged 18), was living together with his mother and elder brother in Tuen Mun. He had formed an intimate relationship with the deceased, Ms Lau Shuk Fan (“Lau”), in early 2009 and, by April 2009, she often spent nights at the appellant’s home. On the evening of 29 April 2009, the appellant killed Lau by repeatedly striking her with a chopper. The forensic pathologist testified that there were 64 separate wounds to Lau’s body, including 50 cut wounds, inflicted with a great deal of force. The scientific evidence was that Lau had been struck with the chopper many times whilst she was either sitting or crouching or lying on the lower bunk bed in the flat and that this was the only place where she had been attacked. 5. According to the appellant, whose account is the only version of the events leading to the killing, he was provoked to lose his self-control during a quarrel with Lau which escalated into a violent attack. He harboured suspicions that Lau was conducting an affair with his brother and, on the evening in question, had confronted her about this on the basis of certain evidence he had found at home that day. He said that he brandished a chopper with a view at first to scaring Lau and challenged her to tell him the truth as to whether she was having an affair with his brother. When she denied this and denigrated him as to his sexual abilities, he got the chopper from the kitchen and this led to a struggle with Lau. There was a lull in the struggle, he said, and he put down the chopper which Lau then used to chop him on the back of the head. The appellant claimed this caused him to lose all self-control and to snatch the chopper from her and to chop her indiscriminately. 6. The appellant therefore relied on the partial defence of provocation to the charge of murder provided for in section 4 of the Homicide Ordinance (Cap.339),[4] contending that he should be found guilty of the lesser offence of manslaughter by reason of provocation. For its part, the prosecution sought to argue that the multiple chop wounds were inflicted by the appellant attacking Lau in a vicious rage and not as a result of any provocation. 7. On 15 September 2011, by a majority of 6 to 1, the jury convicted the appellant of murder. They must therefore have been satisfied that the prosecution had made them sure that the appellant was not entitled to the statutory defence of provocation. The intermediate appeal and leave to appeal to the CFA 8. The appellant appealed his conviction for murder on the ground that the trial judge had misdirected the jury by failing to make it sufficiently clear that the defence was available if the provocation would “or may” have caused a reasonable person to lose self-control and do as the appellant did. The Court of Appeal dismissed his appeal on 20 September 2012, on the basis that, contrary to the appellant’s contention, this had been adequately conveyed to the jury.[5] The appellant’s application for a certificate on a point of law for this Court regarding the provocation direction was dismissed by the Court of Appeal on 26 October 2012.[6] 9. There was then a hiatus in the proceedings and it was not until 5 September 2016 that the appellant applied to this Court for leave to appeal out of time. The delay was explained on the basis that the appellant’s initial application for legal aid was refused and it was not until April 2016 that he received advice from the Clinical Legal Education Programme at the University of Hong Kong which led to the grant of legal aid in August 2016 to pursue an appeal to this Court.[7] 10. Ironically, the point on which the appellant was advised to apply for leave to appeal was not one that was reasonably arguable[8] but, by the time of the leave hearing before the Appeal Committee, this Court had handed down its judgment in HKSAR v Liang Yaoqiang (2017) 20 HKCFAR 1 (“Liang Yaoqiang”) and it was thought appropriate in the circumstances to grant leave to appeal to raise a further ground of appeal based on that decision, namely: “It is reasonably arguable that there is a further departure from the accepted norm in that the Trial Judge had failed to give proper direction to the jury on how to address the issue as to whether an ordinary person would have done what the Applicant did when considering the objective limb of the defence of provocation in the particular circumstances of the case, particularly in the light of the Applicant’s frenzied attack on the deceased with a chopper resulting in multiple deep wounds and the closing speech by prosecuting counsel which urged the jury to consider: ‘Would an ordinary person lose control and use a chopper to chop her to death? Chop her over 40 times while she was lying or crouching in the lower bunk.’ (see page 12E-G of the transcript of the Prosecution’s closing speech).”[9] The risk of an impermissible line of reasoning in provocation cases 11. In Liang Yaoqiang, the Court considered the construction of the words “do as he did” in section 4 of the Homicide Ordinance (Cap.339),[10] which relate to the objective limb of the defence of provocation.[11] The Court concluded that those words, properly construed in the light of the context and purpose of section 4 and the underlying policy of the law to mitigate the penal consequences of a killing carried out in the frenzy of a loss of self-control, meant “to kill the victim (i.e. to form the intent to kill or cause grievous bodily harm and act on that intent) by whatever means” rather than to kill the victim in exactly the manner the defendant did.[12] 12. In view of that construction of section 4, it is impermissible for a jury to reason that: (a) notwithstanding the defendant was in fact provoked to lose his self-control, (b) the scale of the retaliation was out of proportion to the provocation offered, so that (c) the objective question to be asked in assessing whether the defence of provocation was made out should necessarily be answered against him.[13] 13. Although this issue does not arise in every case involving provocation (nor indeed in every frenzied attack case[14]), where there is nevertheless a real risk of that impermissible line of reasoning being pursued, the trial judge should give a suitable direction to counteract that risk.[15] Judge should have given special direction on “do as he did” in this case 14. Both the appellant and the respondent jointly submitted that, in the particular circumstances of the present case, there was a real risk of the impermissible line of reasoning being adopted by the jury when they considered the objective limb of the defence of provocation and that the trial judge misdirected the jury in failing to give proper directions to counteract that risk. For the following reasons, we were satisfied that this submission was made out. 15. In Liang Yaoqiang, the Court held that whether a case is one which requires the trial judge to give a special direction depends on whether: “… the nature and extent of the homicidal act in a given case is such that might lead to the impermissible line of reasoning. It also depends on the course of any cross-examination of the defendant and the content of the closing speeches of counsel. This question must therefore be answered on a case by case basis …”.[16] 16. In the present case, the killing of Lau was the result of a frenzied attack with a chopper resulting in at least 50 cut wounds to her body. The prosecution’s cross-examination of the appellant focused on the precise form and extent of his retaliation in the face of Lau’s allegedly provocative actions and words. This theme was revisited in the prosecution’s closing speech, in particular in the following extract from that speech shortly before its conclusion: “However, if despite of what I said above, you still take a view that the accused had been provoked or might have been provoked to kill Miss Lau by things said or done by her and/or by his elder brother, then you have to consider – then now you have to consider the objective element, i.e. whether an ordinary and sober person, free from drug, of the accused’s sex, age and his characteristics, would have behaved as he did. Would an ordinary person choose to break up with Miss Lau if he did believe that she had an affair with his elder brother? Probably yes. Would an ordinary person ask her to leave his place immediately? Probably yes. Would an ordinary person use physical violence on her? Probably yes. Would an ordinary person lose control and use a chopper to chop her to death? Chop her over 40 times while she was lying or crouching in the lower bunk. Use your common sense and your collective experience of life. You would know an ordinary person would not do as he did.”[17] 17. This part of the prosecution’s closing speech clearly invited the jury to reason that a person with ordinary powers of self-control might have had a range of reasonable reactions in the face of Lau’s alleged provocation but would not have chopped her to death by inflicting over 40 cut wounds. The scale of the actual retaliation by the appellant to the provocation was used as a means to suggest that the response to it went beyond that to which a person with ordinary powers of self-control would have resorted. 18. The risk of the jury adopting that impermissible line of reasoning when considering the objective limb of the provocation defence was also exacerbated by defence counsel’s speech to the jury in which he (quite properly)[18] invited it to conclude, in relation to the subjective question of whether the appellant had in fact been provoked into losing his self-control, that the number of chop wounds, their depth and the short period of time in which they were inflicted showed that this was due to a sudden and temporary loss of self-control. 19. The trial judge’s summing up to the jury on the defence of provocation followed the language of section 4 of the Homicide Ordinance (Cap.339). No criticism attaches to the judge in that regard since this Court’s decision in Liang Yaoqiang was not then available and the concern that led to that decision was not raised before him. But it does mean that the judge did not give any particular direction to counteract the risk of the jury pursuing the impermissible line of reasoning. In the particular circumstances of this case, since that was a real risk, it follows that the judge misdirected the jury by omitting the special direction referred to in Liang Yaoqiang at [124] and there was consequently a departure from an accepted norm to the appellant’s disadvantage such as to constitute a substantial and grave injustice. 20. Accordingly, the appellant’s appeal was allowed and his conviction for murder quashed. Appropriate to order a re-trial 21. Where it allows an appeal and quashes a criminal conviction, this Court has the power to order a re-trial.[19] The principles on which the Court acts when considering the issue of whether to order a re-trial are well-established and were common ground between the parties to this appeal: whether or not there should be a re-trial is a matter of discretion, depending on what justice requires (that being the critical question), and this may involve balancing a number of competing factors some weighing for, and some against, a re-trial.[20] 22. If this Court were to order a re-trial, it would mean that the appellant will have to face a third trial in respect of his killing of Lau. His first trial (in HCCC 312/2009 before Wright J and a jury) resulted in a murder conviction on 17 May 2010 that was quashed by the Court of Appeal (in CACC 169/2010) on 21 February 2011. The re-trial ordered by the Court of Appeal was the second trial (in HCCC 69/2011) which resulted in his conviction on 15 September 2011. A further re-trial would also entail considerable delay since Lau was killed in April 2009 and any re-trial of the appellant now would necessarily take place many years after the events in question and after the appellant has already been remanded in custody for over 8 years. 23. These factors, that a re-trial would mean a third trial for the appellant and that there will have been considerable delay in prosecuting that trial during which period the appellant has been remanded in custody, were the principal matters urged upon the Court by Mr Daniel Marash SC on behalf of the appellant in resisting the respondent’s application for a re-trial. 24. Although they are not factors to be lightly dismissed, we were satisfied that it would be in the interests of justice to order a re-trial in the present case. The charge of murder that the appellant will face is a very serious one and the interests of justice include the interests of the victim’s family and, more widely, the interests of the public in Hong Kong that persons guilty of serious crimes should be brought to justice and should not escape it merely because a judge is subsequently found to have misdirected the jury on a point of law.[21] The questions to be addressed in evaluating the defence of provocation are pre-eminently ones for a jury and it would be preferable for a jury to determine if the appellant’s conviction for killing Lau should be for murder or the lesser crime of manslaughter by reason of provocation. Whilst a third trial on any criminal charge must be an unusual course,[22] it is by no means unprecedented.[23] Since the appellant was sentenced to imprisonment for life, this is not a case where he has already served the whole of his sentence as was the case in Mok Kin Kau v HKSAR, where that factor weighed against a further re-trial.[24] Nor is a re-trial of the appellant likely to be lengthy or particularly complex.[25] 25. Although by the time of any re-trial there will certainly have been a considerable period of time since the killing, that delay has fortuitously worked to the appellant’s advantage in that, but for the hiatus during which he was seeking legal aid (referred to at [9] above), he would not have been able to rely on this Court’s decision in Liang Yaoqiang. That is the only basis on which his appeal against conviction for murder has been allowed, since the ground of appeal for which legal aid was eventually granted was determined not to be reasonably arguable. Any difficulties the appellant may have in recalling the events in question or his previous testimony can be mitigated, at least in part, by reference to his police interviews and transcripts of his evidence at his earlier trials. And the trial judge can, if it appears appropriate to do so, direct the jury to make due allowance in the appellant’s favour for the fact that he has to cast his mind back to events which took place a very long time ago. Furthermore, this is not a case in which it has been suggested that the passage of time has resulted in any specific problem for a re-trial, such as a relevant witness not being available. In these circumstances, the delay, whilst doubtless a relevant consideration, is not one which persuaded us to exercise our discretion against an order for a re-trial. Disposition 26. For the above reasons, we concluded that the appropriate orders to make in disposing of this appeal were: (1) to allow the appeal and quash the appellant’s conviction for murder; (2) to order that he be re-tried on a fresh indictment for murder; and (3) to order that the appellant remain in custody pending such re-trial. Mr Daniel Marash SC, instructed by Morley Chow Seto, assigned by the Director of Legal Aid, for the Appellant Mr William Tam SC, DDPP and Ms Sabra Lo SPP, of the Department of Justice, for the Respondent [1] In HCCC 69/2011 before Saw J and a jury. [2] See Mok Kin Kau v HKSAR (2008) 11 HKCFAR 1 and HKSAR v Shum Wan Foon (2014) 17 HKCFAR 303. [3] CACC 405/2011 (Yeung VP, Lunn JA and M Poon J), Reasons for Judgment dated 11 October 2012 (“CA Judgment”) at [3]-[34]. [4] This provides: “Where on a charge of murder there is evidence on which the jury can find that the person charged was provoked (whether by things done or by things said or by both together) to lose his self-control, the question whether the provocation was enough to make a reasonable man do as he did shall be left to be determined by the jury; and in determining that question the jury shall take into account everything both done and said according to the effect which, in their opinion, it would have on a reasonable man.” [5] CA Judgment at [42]-[46]. [6] CACC 405/2011 (Stock and Yeung VPP and Lunn JA), Judgment dated 26 October 2012. [7] Amended Application for Leave to Appeal (Out of Time) dated 8 February 2017 at [31]. [8] See the Reasons for Determination of the Appeal Committee in FAMC 43/2016 dated 17 February 2017 (reported in (2017) 20 HKCFAR 91) at [9]-[12]. [9] Ibid. at [13]-[16]. [10] See FN4 above. [11] As to the ingredients of the defence of provocation, see Liang Yaoqiang at [8]-[11] and Ho Hoi Shing v HKSAR (2008) 11 HKCFAR 354 at [31]. [12] Liang Yaoqiang at [68], [111]-[114]. [13] Ibid. at [115]. [14] FAMC 43/2016, Reasons for Determination dated 17 February 2017 at [16]. [15] Liang Yaoqiang at [124]. [16] Ibid. at [118]. [17] Transcript of Prosecution’s Closing Submissions in HCCC 69/2011. [18] Liang Yaoqiang at [107]. [19] See Hong Kong Court of Final Appeal Ordinance (Cap.484) s.17(2) and Criminal Procedure Ordinance (Cap.221) s.83E(1). [20] See Au Pui-kuen v Attorney General [1979] HKLR 16 at pp.19-20; Ting James Henry v HKSAR (2007) 10 HKCFAR 632 at [49]; and Kissel v HKSAR (2010) 13 HKCFAR 27 at [269]. [21] Au Pui-kuen v Attorney General (supra.) per Lord Diplock at p.20. [22] R v Chau Mei Ling [1981] HKC 542 at p.545B-C. [23] See Nguyen Anh Nga v HKSAR (2017) 20 HKCFAR 149 at [65]; Liang Yaoqiang at [127]; HKSAR v Lo Chun Siu (CACC 90/2013) unrep., Judgment dated 6 June 2014 at [191]; HKSAR v Wong Wai Man & Others (CACC 459/2001) unrep., Decision dated 27 April 2004 at [3] [24] (2008) 11 HKCFAR 1 at [12]. [25] Compare Ting James Henry v HKSAR (supra.) at [50], where the fact that the original trial was long and complex was treated as a factor of particular significance weighing against a re-trial.