Tens of thousands of additional patrol officers must be placed permanently in local neighbourhoods if a surge in privately-policed "gated communities" and vigilantism is to be avoided, one of Britain's leading officers said yesterday.

Sir Ian Blair, the Deputy Commissioner of the Metropolitan Police, warned that the tradition of "one-nation policing" and the social cohesion it brought was in jeopardy if people turned to private policing to fill the gaps in the public service.