Juries in English courts are to be told about a defendant’s previous convictions as a matter of course for the first time, it was confirmed today.

New rules will come into effect in December, giving juries a right to know before they reach their verdict whether an accused person has been found guilty of the same offence before.

In an additional move announced today, in trials involving child sex and theft offences a judge will be able to order that previous convictions are made public not just for the same offence but for all similar and related offences.

Tony Blair told reporters at his monthly Downing Street press conference: "I accept this is controversial, there are people who believe this undermines the defendant’s rights. But for too long the scales of justice have been weighted in the defendant’s favour and against the victim’s. That is changing."

The change was included in the 2003 Criminal Justice Act and will apply in both magistrates' and Crown courts. The reforms represent a significant change to the way criminal trials take place in England and Wales.

Previously all previous convictions were withheld from the court under the principle of the presumption of innocence. If information about previous bad character did leak out, the trial was generally abandoned and a retrial ordered by the judge.

Today David Blunkett, the Home Secretary, said that the reforms would alert juries to a defendant's previous bad character "without unduly prejudicing the fairness of the trial".

He said: "Trials should be a search for the truth and juries should be trusted with all the relevant evidence available to help them to reach proper and fair decisions.

"The law has recognised for over a century that evidence of a defendant’s previous convictions and other misconduct may be admitted in some circumstances.

"But the current rules are confusing and difficult to apply, and can mean that evidence of previous misconduct that seems clearly relevant is still excluded from court."

Under the Criminal Justice Act 2003, which received royal assent last November, judges will still have discretion to hold back information about convictions if they decide it would prejudice the jury too strongly, but the onus will be on making the details public.

Mr Blunkett said that he intended to name further categories of offences in the future where a defendant's criminal record will be laid bare in court.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• The Times celebrates its 225th birthday
• Heath discussed IMF loan during 1974 crisis
• Britain’s loneliest café opens for business