A senior circuit judge has said that juries should be given written directions in all but the simplest cases.

Judge Keith Cutler, who is based in Winchester, was commenting on a study carried out on behalf of the Ministry of Justice which suggests that two-thirds of jurors in criminal trials fail to understand fully the legal directions given by the judge when they retire to consider their verdicts.

Researchers spent two years analysing 68,000 verdicts in England and Wales, questioning jury members and staging simulated trials with almost 800 jurors.

Judge Cutler told the Today programme that he was very pleased that the research showed the jury system to be "fair, effective and efficient".

He added that jurors were trusted to reach "fair and proper balanced conclusions" but added that the new guideline to be introduced for judges "is to the effect that in all but the most simple of cases, we should consider giving written directions to jurors".