In a move that is likely to embarrass the government, a group of retired generals have come out against replacement of Britain's Trident nuclear system, backing calls from churches and others for the weapons of mass destruction to be scrapped.
In a letter published in the Times newspaper, Field Marshal Lord Bramall and Generals Lord Ramsbotham and Sir Hugh Beach denounce Trident, calling it "irrelevant".
Former prime minister Tony Blair gave the go-ahead to replace the system in 2006 at a cost estimated in the region of £20 billion. Current PM Gordon Brown has backed the plan. His own Church of Scotland opposes it.
The senior military ex-leaders say in their letter that the United Kingdom is too dependent on the US when it comes to defence.
They write: "Nuclear weapons have shown themselves to be completely useless as a deterrent to the threats and scale of the violence we currently face, or are likely to face - particularly international terrorism."
They go on: "Our independent deterrent has become virtually irrelevant except in the context of domestic politics.
"Rather than perpetuating Trident, the case is much stronger for funding our armed forces with what they need to meet the commitments actually laid upon them. In the present economic climate it may well prove impossible to afford both."
But the retired officers said the unilateralist case was now the only way forward and refuted arguments that the defence system was essential for a place at the "top table" of the United Nations Security Council.
The Trident system - made up of submarines, missiles and warheads - are due to end their working lives in the 2020s, reports the BBC.