The British government has failed to offer any coherent explanation of its intention to increase its stockpile of nuclear warheads by 40 per cent. And this omission relates to the broader issue: why it is thought necessary that Britain should have nuclear weapons at all. Two comprehensive statements have just been published, one on foreign policy and one on defence policy, and both of them treat the answer as so obvious that it does not need stating.

It is hard to avoid the conclusion that there is another reason – far from being obvious, the argument does not exist. The Emperor, in other words, has no clothes. There is a political consensus that criticising Britain’s nuclear weapons programme would be disloyal. Yet it is an open secret that even in the defence establishment, no strategic military purpose behind Britain’s possession of nuclear weapons can be discerned. Neither of the two government policy statements even attempts to do so.