Amongst a raft of law and order measures announced, the ending of the "double jeopardy" rule is set to be one of the most controversial.

Accepting one of the key reforms recommended by the Macpherson report on the murder of Stephen Lawrence, the government believes that "compelling new evidence" should lead to suspects being re-tried for a crime they have already been cleared of.

When Macpherson recommended the reform, the then home secretary, Jack Straw, asked the Law Commission to examine the proposal.

The commission gave the change its backing and said that it should be retrospective in its application - opening the door to a re-trial of those acquitted of the murder of Stephen Lawrence.

The reform will provoke opposition from civil liberties groups who will argue that changes to the ancient principle could put innocent people at risk of repeated prosecutions.

It is expected that only the Court of Appeal will have the authority to order a re-trial if it regards new evidence, such as that from DNA testing, to be compelling.