Now that's what I call a Neighbourhood Watch scheme!

We live, we are told, in a feral society, where lurking on every street corner is a predatory youth clad in hooded top and trackie bottoms, with a kitchen knife secreted somewhere about his person.

At least that is the image of urban life portrayed by the more scaremongering quadrant of the media. And for those who lap up such paranoia, and who happen to live within the sound of Bow Bells in London, rescue is on hand courtesy of the British Army.

For "Our Boys", as The Sun generically refers to any soldier of indistinct gender, have been given the go-ahead to set up six batteries of Rapier anti-aircraft missiles on rooftops in the vicinity of London's Olympic Stadium.

It's all part of the ring of steel encircling the capital to protect the London 2012 games from a 9/11-style terrorist attack. Quite what happens when an inbound airliner is blown out of the sky above a city of eight million people by a warhead travelling at three times the speed of sound is not really known, but we must presume that those behind this extreme policing know what they're doing.

Still, together with helicopter-borne snipers, an aircraft carrier moored in the Thames, RAF Typhoon jets stationed at Northolt, and the SAS ready to rope in through any window like Monty Python's Spanish Inquisitors, London will be, in theory, the safest city on the planet for the three weeks the Olympics take place.

The big question, though, is whether the Army will have anyone left to take the missile launchers down afterwards. With military redundancies taking place almost as soon as troops return from deployments in Afghanistan, it may require private enterprise to bring the rockets down. Unless they get left up there, along with footballs, single training shoes and all the other detritus that you see on London housing estates.

Some residents, inevitably, are complaining that the siting of weapons designed originally to stop Russian bombers attacking British airfields will make them a target themselves. They're missing the point: while politicians argue over London's Olympic legacy, and whether to let West Ham United have the stadium, or an athletics club, or another giant shopping mall, those with guided missiles on their rooftops will come out best.

I mean, who's going to nick a car when that sort of firepower is going to rain down on you?