BORIS TO LAUNCH MAYORAL CAMPAIGN

The colourful Conservative MP for Henley will be fighting for the right to take on Labour's Ken Livingstone in next year's poll.

Mr Johnson has urged the public to "take a risk" by personally tackling thugs causing trouble on the streets - advice at odds with the police.

Mr Johnson said: "What drives me mad is when you see some kids behaving badly at the top of a double-decker bus, but no one has the guts to intervene because they're scared.

"If one person speaks up, they are seen as brave - but everyone else keeps quiet. What if everyone together on that bus were to intervene? We need a bit more willingness."

Asking in an interview for the News of the World whether people should be worried about getting stabbed, the Tory front-bencher replied: "Your chances of getting stabbed are very small. You know and I know that your chances are microscopic."

He said it drove him "wild" that individuals who did step in often got into trouble with the law themselves.

"You have to stamp out this kind of political correctness, and tilt the balance back in favour of the active citizen taking a risk, not just on their own behalf, but for their whole community."

A Met spokeswoman said: "The police advice has always been not to step in and be a 'have a go hero'. You should contact the police. You have to be aware that things can escalate, and are you in a position to defend yourself?"

Mr Livingstone, the current Mayor, said Mr Johnson failed to address the real issues for tackling crime in London. "The central issue to fight crime in London is to increase police numbers and provide the Met with adequate resources," he added.