1. The Appellant was convicted after trial of one count of trafficking in a dangerous drug, contrary to section 4(1)(a) and (3) of the Dangerous Drugs Ordinance, Cap.134. On a stop-and-search by the police, he was found in possession of a box containing cocaine and also in possession of the keys of a car beside him in which a further quantity of cocaine was found. 2. The Appellant’s case at trial was that he did not know what the box contained or of the presence of the drugs in the car. He did not give evidence at the trial but relied on the content of his video recorded interview (“VRI”) in which he explained that he had earlier handed his car over to a “Hak Chai”, who was a car repairman, to quote for its repair and he had arranged to meet Hak Chai on the night in question to pay him. When he arrived, Hak Chai had said he had to go to the lavatory and so asked the Appellant to wait by the car for him. Hak Chai left the Appellant with the car key and a box, saying that there was something valuable inside it and that someone would come and collect it. 3. However, there were three mistranslations in the English transcript of the VRI, which suggested that the Appellant had already paid Hak Chai and that the car had been fixed. As a result, the Trial Judge, who did not speak Cantonese, commented in the course of her summing-up to the jury that the Appellant’s answers in the VRI were inconsistent and that there were chronological difficulties in his account. 4. The Court of Appeal considered that the Judge had been misled by the mistranslations but concluded that the mistranslations did not result in any material unfairness for two reasons. First, much of what the Judge said was directed at the generally confused and muddled nature of the Appellant’s answers in his VRI. Second, by requesting to review the VRI, the jury had gone to the primary materials to determine for themselves what to make of the Appellant’s account. This was coupled with the observation that the bulk of what the Appellant said in the VRI should be clear to the native Cantonese speaker. 5. The issue in the appeal was whether the Judge's comments relying on the mistranslated portions of the VRI may have resulted in the Appellant not receiving a fair trial. 6. The Court of Final Appeal held that whether a mistranslation leads to unfairness in a trial will necessarily depend on the nature and context of the mistranslation and its importance to the issues in the particular case. 7. In the present case, there was only one issue, namely whether the Appellant knew the drugs were in the box and in the car. The contents of the VRI and the Appellant’s credibility were critical to that issue. Therefore, the Judge’s comments on the basis of the mistranslated portions of the VRI resulted in the summing-up being unbalanced and unfair to the Appellant. 8. The Court did not agree that the unfairness had been overcome by the reasons given by the Court of Appeal. It was speculative to assume all the jurors were native Cantonese speakers and to conclude that, by requesting to review the VRI, the jury must have done so in order to check the accuracy of the Judge’s comments on the Appellant’s answers. More importantly, it devalued the significance of the summing-up in the trial process, as the jury was bound, as well as entitled, to take the Judge’s summing-up into account in its deliberations. 9. The Court therefore concluded that it had been shown that substantive and grave injustice had been done to the Appellant since, in the circumstances, the Judge’s comments based on the mistranslations did result in the Appellant not receiving a fair trial. 10. The Court allowed the Appellant’s appeal, quashed his conviction and ordered a re-trial.