That is not the logic, and it is the reason why we have the non-proliferation treaty, to which we are signatories. Everything that the Government have proposed is in line with that treaty, as is resisting other states developing nuclear weapons. By the way, I have the greatest of respect for the hon. Gentleman, as well; we North Yorkshire MPs have to stick together. However, he must not think that if we announced today our intention not to have a nuclear deterrent in future, other countries—those in Tehran, for example—would say, "What a relief! We are now going to abandon our nuclear intentions." That is not the way the world works, as he and I know; we simply have to make the realistic decision.
I have nothing but respect for those who wish the world could be free of nuclear weapons—most or all of us do—but our own total disarmament would no more make it so than wishing it so would. Crucially, the absence of our own nuclear weapons would make us more dependent, not less, on the United States of America. It is perhaps a paradox that those who oppose this decision are often among the fiercest critics of the United States; yet, in the ultimate crisis, such people would leave our security wholly dependent on the credibility and resolve of the White House—or of the Élysée—and its readiness to risk everything for the sake of Britain. Can we always be confident of that—that that would apply to the occupant of the White House for decades to come? I do not think that we can have that confidence.
For all these reasons, the arguments in principle for replacing our deterrent therefore seem to me overwhelming. The risks of not replacing it far outweigh the difficulty and expense of doing so. Furthermore, the advantages of a submarine-launched system, which is as invulnerable to attack as any weapons system in the modern world can be, also seem overwhelming. So we support the maintenance of a continuous at-sea deterrent, which until now has necessitated possession of four ballistic missile submarines. We would of course like to know when the Government think it will be possible to decide whether the new class of submarines can operate with only three vessels. The alternative of submarine-launched cruise missiles has also been suggested, but we share the Government's judgment that that would not only require the development of new technologies, but would require a submarine to be far closer to its potential target to have any deterrent effect. We also share the Government's view that the possession of ballistic missiles that can be launched from anywhere in the world toward anywhere in the world is an important part of successful deterrence.