Britain would have "much more leverage" in international politics if it

ditched the nuclear weapons it uses to protect itself from attack, according to a Bradford academic.

Dr Shaun Gregory, a leading authority on nuclear weapons issues, told an influential Commons committee there

was no need for the Government to replace the UK's ageing Trident submarine deterrent.

He believes the UK is protected by nuclear weapons by being so inextricably linked to American foreign policy.

And he suggests the nation would be in a "strong moral position" to assert "diplomatic leadership" if it scrapped its nuclear missiles.

Dr Gregory, head of the University of Bradford's department of Peace Studies, made his comments as he addressed the Commons' powerful Defence Select Committee.

The all-party committee is taking evidence from experts as part of an investigation called The Future of the UK's Strategic Nuclear Deterrent.

Dr Gregory said: "I don't believe that if Britain gave up its nuclear deterrent then that would lead to great international denuclearisation. That

is too simple. But the point is that Britain's nuclear weapons capabilities, partly because of our dependence on the USA, is largely irrelevant. If we have or

don't have them isn't going to make much difference."

He said any foreign power threatening a nuclear attack on Britain would compromise American economic interests - and the US would respond by warning it would retaliate.

Dr Gregory said if Britain "turned away" from nuclear weapons it would be possible to "assert diplomatic leadership" on the international stage.

He said: "We would be in a very strong moral position. I think this would give us much more leverage rather than being carried along in the tow of the USA.

"I think we have a chance to cut ourselves free from American policy in this respect and that would be enormously healthy."

The Trident fleet is not due to be decommissioned for about 20 years. But Ministry of Defence chiefs must soon decide whether, if the UK is to

keep an independent nuclear deterrent, to replace or upgrade the submarines.

Prime Minister Tony Blair said no decision had been taken, but he believed it was best that the UK retained the nuclear capability. He believes it important to possess a strategic nuclear deterrent as long as other countries have nuclear weapons.