An urgent review of the law to prevent offenders from being released from prison on a technicality was announced by Charles Clarke, the Home Secretary, yesterday.

He said the Government was ready to implement recommendations first made five years ago for a reappraisal of the test used to quash an "unsafe" conviction. One option to be considered is for English law to adopt the Scottish verdict of "not proven", which juries can return when they are not convinced of a defendant's innocence but neither can guilt be shown beyond reasonable doubt.

The review of Court of Appeal rules for deciding what is a miscarriage of justice could result in legislation to limit the circumstances in which an error in the trial process can be used to quash a conviction. Mr Clarke said the fact that mistakes might have been made did not mean that there had been an injustice.

"The more the legal system clearly relates to the conduct of individuals who have done things, or have not done things, and the less it relates to legal technicalities, the better it is for the transparency of the legal system as a whole," he said.

"What individuals want to see is a legal system which correctly finds guilty those who are guilty and acquits those who are innocent, with respect to what they did or did not do rather than whether the legal process was or was not correctly followed."

Mr Clarke said that raising the barrier for an acquittal would require careful consideration, though it would mark a return to the position before 1995 when judges could uphold convictions in certain circumstances even if errors had been made at the trial.