R v Andre Mathurin

In a criminal jury trial, the judge must remain a neutral arbiter. A judge may ask questions to clarify evidence, but must not test or challenge a defendant’s account in a way which appears to take the prosecution’s side. This is especially important where the defendant’s credibility is central to the verdict.

When assessing safety, the appellate court must consider the effect of the interventions on the trial as a whole. A strong prosecution case, an uninterrupted examination-in-chief and a fair summing-up may not cure improper judicial questioning which significantly weakens the defence on the decisive issue.

The appellant was convicted at the Crown Court at Snaresbrook of supplying a controlled drug of Class A. The prosecution alleged that he had taken a bag containing heroin into another man’s flat. He said that the bag contained a charger and that he had later returned to deliver tools.

He appealed with leave of the single judge. His sole ground was that the trial judge’s questions during cross-examination improperly challenged his account and rendered the conviction unsafe. The central issue was whether the judge’s interventions had impermissibly entered the arena and affected the jury’s assessment of the appellant’s credibility.

1. Appeal allowed. The court quashed the conviction because it could not say that it remained safe.

2. The court endorsed the principles stated in R v Inns [2018] EWCA Crim 1081. In an adversarial criminal trial, the jury is the tribunal of fact and the judge must act as a neutral umpire. A judge may properly ask questions to clarify evidence, but it is not the judge’s role to cross-examine a defendant or to interrupt the presentation of the defence account unnecessarily.

3. The judge’s interventions went beyond clarification. They identified possible weaknesses and alternatives in the appellant’s explanation for carrying the bag, returning to the flat and seeking help with tools. The questions would have conveyed judicial scepticism about the defence and created the appearance that the judge was taking sides. That was an impermissible entry into the arena.

4. The prosecution case was strong, the appellant had completed his evidence-in-chief without inappropriate interruption, and the summing-up fairly directed the jury that the facts were for them. Those matters did not preserve the safety of the conviction. The jury had to reject the appellant’s account before it could convict, so his credibility was central. The improper interventions significantly weakened that account on the decisive issue.

5. The court ordered a retrial on count 1. It directed service of a fresh indictment under rule 10.82 of the Crim PR, rearraignment within two months, and retrial at Snaresbrook Crown Court before an appropriate judge.

• Court of Appeal (Criminal Division): Allowed the appeal, quashed the conviction and ordered a retrial: [2025] EWCA Crim 1254.
• Crown Court at Snaresbrook: Convicted the appellant on 11 July 2024 of supplying a controlled drug of Class A.