London police say nearly 700 charged over riots

A US crime expert enlisted by Cameron to help curb gangs after this weeks riots has said, that solving the problem was more complex than just arresting people.

Former New York police commissioner Bill Bratton who was a key figure in imposing zero-tolerance police in New York said the solution was robust and community based policing was necessary to nip gang culture in the bud.

"It is going to require a lot of intervention and prevention strategies and techniques," Bratton told in an interview in US.

He said he had agreed to visit Britain in coming months to give advice.