Cameron in street crime pledge

He said there needed to be "far more" on-the-spot action and pledged to take on critics who argue the tactic alienates ethnic minorities who are more likely to be stopped.

In an interview with The Sun newspaper, he argued black and Asian youngsters would benefit most from a tougher regime as they were the ones being stabbed and shot.

He told the newspaper: "This is a moment in our history when we have to wake up, sit up and have massive social, political and cultural change.

"We are never going to deal with it unless we free the police to do far more stopping and far more searching. I am quite clear the current rules have to go."

He added: "Stop and search rules were put in place to protect young black and Asian British kids. Now it's the young black and British Asian kids that are being stabbed and shot and the rules are getting in the way of protecting them.

"We will carry out a review to see how we would do it, and then we would implement it very rapidly under a Conservative government."

Racist attitudes in the police had now been changed, he said, meaning the powers could be extended without charges of prejudice being levelled at officers.

Official figures showed last year that black people were seven times more likely than whites to be stopped and search by the police in 2006, an increase on the previous year. Asians were about twice as likely to be stopped and searched.

Mr Cameron's call follows a similar suggestion last year from Keith Jarrett, president of the National Black Police Association, which sparked heavy criticism.