Hands off our subs

It is 2030. The nightmare has happened. Nuclear missiles have lifted off from a nation in the middle east. They are heading for Britain, and will strike within the hour.

Regrettably, 20 years earlier Britain decided that it would not keep a nuclear arsenal. The last British Trident submarine was phased out in 2025. The prime minister has no button to press. The missiles fall, gutting the sceptred isle. The PM turns to the remaining western nuclear powers for help: America and France. But the aggressor nation still has missiles left, and it is clear that in the event of any retaliatory strike, Washington or Paris will share the fate of London. France declines to act. In America the debate is longer and harder fought, but in the end the result is the same. The US missile defence system still doesn't work reliably, and the US is unwilling to lose cities purely to avenge the British. The attackers knew this would happen: this is why unarmed Britain was the target.

In another scenario, Britain still has some working nuclear missiles. However, because of the desire for a truly independent deterrent, they are in land silos rather than submarine-launched. Their location is well known, and it is almost certain that some of the incoming missiles are targeted on them. The PM must order a counterstrike at once, or her missiles will be destroyed.



However, the distraught president of the aggressor country is now on the phone. He says the attack is none of his doing. Extremists within his security forces fired the missiles against his orders. He begs the PM to hold her hand. Surely his country's innocent millions do not deserve to die for the actions of a few lunatics.

Perhaps the prime minister launches them anyway, assuming the missiles can be ready in time—by no means a certainty. This would be a dreadful crime if the president was speaking the truth—which isn't impossible. Perhaps she decides that two wrongs don't make a right, and chooses not to retaliate in ignorance of the facts—thus losing her chance to retaliate at all.

In still another scenario, Britain has decided to retain submarine-based weapons. These cannot realistically be taken out. In this case, the attackers would have to be people who simply didn't care about a response. Such people would probably target Israel or the US rather than Britain. Even if Britain does get hit, the prime minister is in no hurry here; her submarines can hold their fire for months if need be, and the facts can be established.

The choice between these scenarios is upon us. It is decision time for Trident, or its replacement. The anti-Trident lobby alleges that the government has already decided to extend the life of the Trident submarines with US support, at a cost of perhaps £20bn. They say this would be a scandalous waste of money, although we often spend more to get less without any objection (the Eurofighter springs to mind).

But the truth is that the only option cheaper than renewing Trident is unilateral disarmament. Few in the anti-Trident lobby advocate this openly, but it is what many of them want. Some suggest that Britain build its own missiles, to be independent of the US. Only the most deluded would claim that this could be done for as little as £20bn.

In fact, it is doubtful whether we can build our own missiles at any price. Britain has never produced a successful long-range rocket. Even vulnerable land-based weapons, if they could be made here, would cost far more than £20bn and take decades to arrive.

Perhaps it is worth £50bn to have a fully British deterrent, even if a rather poor one, but it is hard to see why. Trident is as good as there is, and it is fairly independent. (Yes, it can be launched without US assistance: it merely loses some accuracy in this case.) A total cut-off of US support is vanishingly unlikely, would take years to really affect our capability, and we could always boot the Americans out of Fylingdales in response.

But why even choose that path? Labour MPs should not allow an understandable dislike of George W Bush to put them off everything American. In particular, they shouldn't turn down a relatively economical extension of Trident unless they are genuinely willing to spend scores of billions more on home-grown weapons.