A defendant’s right to fair trial has long been the most important principle in criminal justice. The common law principle governing the judge’s intervention ensures a fair trial of defendants. In a recent decision of HKSAR v Lai Oi Yan [2016] 3 HKLRD 273, the Court of Appeal (the “Court”) has clarified the test as to when judicial interventions as an appeal ground would lead to a conviction being quashed.

The Appeal Case

Case History

Lai Oi Yan (“D”) was charged with two counts of conspiracy to steal. It was alleged that she, as a banking officer, logged into the bank’s database and obtained customer information for her co-conspirators to steal money from those accounts. At trial, the prosecution relied on D’s admission in police notebook entries and a sudden increase in her wealth shortly after the thefts took place, but D denied the alleged admission. Despite this defence gave rise to voir dire, the trial judge admitted D’s admission. D was convicted by the jury and was sentenced to a total term of 10 years’ imprisonment.

Appeal Grounds

D sought leave to appeal against her conviction on the grounds that the trial judge had erroneously interfered with the proceedings and was biased against D.

The Court’s Decision

Citing R v Yeung Mau Lam [1991] 2 HKLR 468 and Chan Kam Keung v HKSAR (2008) 11 HKCFAR 664, the first question taken by the Court is whether the judge’s conduct would have caused the informed bystander listening to the case to say that the D had not had a fair trial, taking into account the long standing common law adversarial system in which judges shall remain impartial from proceedings rather than taking an active role to investigate the facts of the case.

Judge’s Role

The Court cited a list of cases in affirming that, the judge is, and should at all times be, a neutral third party holding the balance between prosecution and defence so as to ensure that the case against the defendant proceeds properly and fairly in accordance with the rules of evidence and procedure.

Test for Assessing Judge’s Intervention

The Court has divided the analytical process in deciding whether judge’s intervention amounts to an appeal ground for quashing convictions into four stages.

Stage 1

As identified in Jones v National Coal Board [1957] 2 QB, when judicial intervention is a ground of appeal, the Court should first consider whether such intervention is made for the purpose of clarifying the evidence; or is made for a legal procedural or evidential purpose; or is made in the exercise of a case management function (the “Purposes”). If so, then the intervention will generally be considered as proper, save and except where the interventions are made in an aggressive, sarcastic, disbelieving or denigratory way, which the appellate court may find to be a sign of court’s hostility towards the defendant and therefore affects the fairness of trial despite the perfectly legitimate reason behind. It should be noted that actual bias on part of the judge is not necessary for establishing that fair trial is impaired. The court is only concerned with how a judge’s conduct would appear to an informed bystander.

Stage 2

If the interventions are made not for the Purposes, then the Court needs to consider how these interventions have impacted on the fairness of the trial and affected the jury, the defence counsel and the defendant. In R v Hamilton [1969] Crim LR 486, it was held that the judge’s interventions must not bear the effect which (i) invites the jury to disbelieve the evidence of defence or (ii) makes it really impossible for defence counsel to perform his or her duty in presenting the defence case or (iii) prevents the defendant from doing himself justice and telling the story in his own way.

Stage 3

If the appellate court does find that the trial judge had made interventions bearing any of such effects, the court has to determine whether, in such context, the conviction is still safe and/or whether the trial is still fair.

Stage 4

If the intervention does not bear such effect, the last issue that the Court needs to consider is whether, even in the absence of any effect as mentioned in Hamilton and even though the court opines that the conviction is safe, whether it can still be said that the defendant did not receive a fair trial. Decision of Randall v The Queen [2002] UKPC 19 suggested that there may be a situation where the appellate court is bound to condemn the trial as unfair and consider the conviction as unsafe.


Having set out the general rules, the Court applied the above principles to multiple interventions made by the trial judge in D’s case. In particular, the Court found that when the trial judge interfered with D’s examination-in-chief by direct questioning, he referred to the offense of accessing a computer with a criminal or dishonest intent under s. 161 of the Crimes Ordinance (Cap. 200) (“CO”). And he suggested that it does not matter what the ulterior motive of the access is, the mere fact that access is dishonest and without authorisation can amount to a crime.

First, the Court considered such reference was distracting and wrong because D was not charged for dishonest use of computer, but conspiracy to steal under ss. 159A and 159C CO. As such, the said intervention fell outside the Purposes as identified in Jones.

Second, the Court considered such erroneous statement of law as highly prejudicial to D because the jury may have the impression that D may have been dishonest. Further, the Court found that the trial judge’s intervention not only had invited the jury to disbelieve D’s evidence, but also prevented D from doing herself justice and telling the story in her own way. As such, the Court allowed the appeal and quashed D’s conviction.


This case highlights the importance of judicial impartiality and upholds the fundamental value of our adversarial system. It is to be welcome and lawyers would be more vigilant in reviewing whether the trials of their clients have been a fair one and not tampered by excessive intervention from the trial judge or magistrate.

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Important: The law and procedure on this subject are very specialised and complicated. This article is just a very general outline for reference and cannot be relied upon as legal advice in any individual case. If any advice or assistance is needed, please contact our solicitors.
Published by ONC Lawyers © 2016