The Trident system could cost £20bn to replace
The UK should take a lead on nuclear disarmament by giving up its Trident weapons system, a retired Nato military commander has said.
General Jack Sheehan said he thought the UK was "very close" to giving up nuclear weapons.
His comments follow calls for a rethink on the renewal of the Trident system from other retired military figures.
Its supporters say that it is still essential that the UK should maintain its independent nuclear arsenal.
The Trident system - made up of submarines, missiles and warheads - are due to end their working lives in the 2020s.
Former prime minister Tony Blair gave the go-ahead to replace the system in 2006.
Gen Sheehan, a former Supreme Allied Commander Atlantic for Nato, told BBC Radio 4's World Tonight: "I think the UK is very close to saying we're the first permanent member of the Security Council to do away with nuclear weapons.
Critics argue it would risk being a gesture that made Britain less safe... those in favour say it could help de-legitimise nuclear weapons
BBC security correspondent
"I think it is entirely possible that the British government, for a lot of good reasons, could do it and it would lead the world."
Gen Sheehan said he believed such a move, were it to happen, would have a significant international impact.
"All of a sudden you call into question why the French have a system," he said.
"It creates an impetus for the US and Russia to kind of move away from this position they're currently in, to start a dialogue to build on."
But he said an "act of political courage" was necessary for such a change to occur.
BBC security correspondent Gordon Corera said the ageing nature of Trident meant that a decision is needed on what comes next.
On the possibility of UK nuclear disarmament, our correspondent said: "Critics argue it would risk being a gesture that made Britain less safe whilst having negligible impact internationally.
"Those in favour say it could help de-legitimise nuclear weapons and stem the tide of states seeking the bomb, undermining, for instance, Iranian claims of double standards."
Gen Sheehan's comments echo similar sentiments expressed by other retired senior military officers, such as Field Marshal Lord Bramall and Gen Sir Hugh Beach, who have argued that nuclear weapons are too costly and are of little use.
And Gen Lord Ramsbotham told the BBC that the "huge" £20bn expense of renewal has to be questioned.
Listen to this story on BBC Radio 4's World Tonight at 2200GMT on Thursday 29 January, or on the BBC iPlayer up to seven days after broadcast.