Destroy Iran's nukes to save our cities

One of the most terrifying possibilities the world faces is that al-Qa'eda, or some other Islamist group, gets hold of a nuclear bomb. Islamist terrorists are certainly trying to obtain one: Osama bin Laden has issued a document entitled "The Nuclear Bomb of Islam", which insists it is "the duty" of Muslims to acquire a nuclear bomb in order to use "as much force as possible to terrorise the enemies of God".

The Foreign Office's senior counter-terrorist official has "no doubt at all" that Islamist terrorists are actively seeking a nuclear device. "There are people" he adds dryly, "for whom exploding a nuclear bomb in a city would be a triumph for the cause."

Deterrence breaks down as a consequence. If they could get hold of a nuclear bomb, Islamist terrorists would have every incentive to use it to cause as much destruction as possible in an "enemy" country such as Britain or America - and there's no threat we can brandish to stop them.