British Prime Minister David Cameron pledged yesterday a “zero tolerance” crackdown after recent urban riots, fuelling a row over plans for the US “supercop” behind the strategy to advise the government.

Police chiefs in Britain criticised Mr Cameron’s decision to hire ex-New York police supremo Bill Bratton to help prevent a repeat of the violence in which five people died, saying a home-grown policy would be better.

“We haven’t talked the language of zero tolerance enough, but the message is getting through,” Mr Cameron told The Sunday Telegraph newspaper.

A four-day frenzy of looting and arson in London and other major English cities has sparked a nationwide debate on the causes and possible responses, with just a year to go until the capital hosts the 2012 Olympics. The Conservative premier accused some people of over-complicating explanations for simple criminality but admitted that underlying social factors including “deeply broken and troubled families” had to be addressed.

“They were nicking televisions because they wanted a television and they weren’t prepared to save up and get it like normal people. The complicated bit is why are there so many, why is there this sizeable minority of people who are prepared to do this?,” he said. In a phone call with Mr Cameron, US President Barack Obama commended the “steadiness” shown by politicians and the police in their handling of the riots, Downing Street said.

But Mr Bratton himself said zero tolerance is “a phrase I hate”, listing instead a raft of measures including understanding how gangs work, using injunctions to curb their activities, and getting former members to help intervene.