Unless it is placed under shared control with our closest allies, who would also be required to share the costs.
Nuclear weapons and their proliferation is one of the biggest threats facing mankind, yet our politicians are currently proving incapable of dealing with it. The way things stand - and are developing - at the moment, it is just a matter of time before, through design, accident, or misunderstanding nuclear weapons are used, and thousand, millions, possibly 10s or even 100s of millions of people will die, perhaps not in the initial exchange, but in the aftermath. And our children will look back and ask WHY?! WHY did WE allow this development, this INSANITY, to happen?
The British and French governments (which, as a European, are the ones that concern me directly and on which I may exert some, very small, influence) have both signed the nuclear non-proliferation treaty and are very strongly opposed to other governments acquiring nuclear weapons, but hypocritically they insist on retaining and periodically updating their own nuclear arsenals and delivery systems.
All the arguments put forward for retaining our own nuclear capability can be (and are) also put forward by other governments (Iran, for example), the rejection of which by Britain and France is blatant hypocrisy.
If there is to be any hope of curbing nuclear proliferation the British and French governments must be persuaded of the necessity for THEM to relinquish their own independent, national nuclear deterrents, handing them over to an international authority, which it should be our urgent priority to work out a structure for and to create. Not an easy task, granted, but an urgent and absolutely essential one.
Advocating unilateral nuclear disarmament would be folly, since it would be an invitation to other, nuclear-armed governments, less democratic and well-intentioned than our own, to dominate us through nuclear blackmail, or even attack. We NEED a nuclear deterrent, but it needs to be under democratic international control, instead of national control.
It is the desire (perceived need) of state governments for their own "national" deterrents, i.e. the power and status that goes with them, which is driving, and will continue to drive, nuclear proliferation.
Thus, it is imperative that Britain and France take the initiative in finding a way of placing their own national deterrents under international control (perhaps in stages, in order to facilitate the process). Once they have done that, then they will be in a position, credibly and without hypocrisy, to demand from other governments that they do not seek to acquire national nuclear deterrents as well.
Finding the right structure for this international authority is absolutely essential, because of the trust that must necessarily be placed in it. It will not be an easy task, so the sooner we set about it in earnest the better.