TRIDENT AND UK'S NPT OBLIGATION...

We are committed to NATO as a nuclear power and there is no prospect of us
discontinuing that alliance or of the United States ceasing to provide NATO
with its nuclear capability. In those circumstances it makes no sense for us
to renew our own national nuclear weapons at enormous cost when there is a
very great need for tactical and battle ground weaponry for use in the many
fields of operations to which we are committed.
The other issue, which is more important in my view, is that Britain is a
signatory to the non-proliferation treaty that commits its participants to
work towards the elimination of nuclear weapons. In my view that is not
compatible with a full scale replacement of our nuclear capability.
Continued protection from a nuclear deterrent under the NATO umbrella is
adequate if we are as committed, as we claim, to our international
allegiance to the US and the other NATO members. Apart from anything else,
when we commit to international treaties we must mean what we say and do
everything in our power to honour the obligations that we have undertaken.

SOURCE: LIBERTARIAN BLOG.
http://malpoet.spaces.live.com/Blog/cns!3FE748F519987B81!245.entry