Blair: Unwise to give up nuclear deterrent.

Tony Blair has announced plans to replace the Trident nuclear weapons system but said the government would cut the number of warheads by 20 per cent and consider reducing the number of submarines to three.

"The whole point about the deterrent is not to create the circumstances in which it can be used but on the contrary to try to create circumstances in which it is never used," the prime minister said.

Attempts by Iran and North Korea to develop nuclear weapons meant that "it would be unwise and dangerous for Britain, let alone any of the other nuclear powers, to give up its independent nuclear deterrent".

Mr Blair said the new system would be built within the UK, protecting thousands of British jobs.

He added that it would be unwise to rely on nuclear protection from allies as "the independent nature of the British deterrent is again an additional insurance against circumstances where we are threatened but America is not".