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Trident

Again, my hon. Friend is absolutely right to say that these are fine matters of judgment in difficult circumstances that we are, of necessity, predicting—they are hypothetical. I can see a situation—let us hope it never happens—in which states with their own nuclear weapons capability are sponsoring terrorism and encouraging the use of chemical, biological or nuclear weapons capability. We do not ever want to be in the position of using our deterrents, but if states had nuclear weapons capability and were threatening our country they might be less willing to do so if we had the nuclear deterrent. That is the judgment that we have to make. I repeat that the idea of the deterrent is not to use it but to try to create circumstances in which it is never used, which is why when people debate the morality of having nuclear weapons or not, it is merely another way of having the debate about whether deterrents deter. If they deter, it is sensible to have them; if they do not, obviously it is not. That is why this thing is best decided on the basis not of what we might do in a particular situation but of what might deter others in actions we wish to deter.