Cops slam Cameron plan

British police chiefs have hit back at Prime Minister David Cameron's plans to enlist a US crime expert after last week's riots, as the conservative leader vowed "zero tolerance" against street violence.

Cameron, criticised by some in his party as being too liberal on crime and punishment, has taken a tough stance after four nights of looting and arson hit cities across England last week.

"We haven't talked the language of zero tolerance enough, but the message is getting through," Cameron said in the Sunday Telegraph.

The prime minister, who has suggested the initial police response to the riots was too timid, has enlisted former New York, Los Angeles and Boston police chief William Bratton to advise his coalition on how to tackle street gangs, which he blamed for much of the violence.

But senior police officers, who have criticised the Conservative-led coalition's plans for police cuts, have reacted sceptically to the plan.