THE bill for renewing the Trident nuclear weapons system has soared to more than £205 billion, according to a report by the Campaign for Nuclear Disarmament (CND).

It has calculated the sum on the basis of official figures, answers to parliamentary questions and previous costs of items including nuclear warheads and decommissioning nuclear reactors.

David Cameron’s Westminster Government is expected to ask MPs soon to vote to replace the existing Trident fleet with four new nuclear submarines which would continue to be based in Scotland on the Clyde.

The Prime Minister is determined to proceed with renewalwhich are based on the Clyde despite opposition from the SNP, Scottish Labour and the Greens.

“These new calculations, drawn from actual government figures, show that the bill has spiralled beyond all expectations,” said Kate Hudson, CND general secretary. “£205 billion of public money is a huge amount. Pouring it into a nuclear weapons system that experts say could be rendered obsolete by new technology is hardly a wise choice. Far better to spend it on industrial regeneration, building homes, tackling climate change or meeting our defence needs in usable ways.”

SNP defence spokesman Brendan O’Hara said the sum suggested the project costs were “staggering and out of control”.

"These figures are just staggering – and if even remotely accurate show the whole project is out of control before a vote has even been taken in parliament to renew,” he said.

"The escalating cost of this immoral weapon must now make the UK Government stop the whole renewal. The SNP will take every opportunity to vote against Trident. It is obscene and completely redundant and Westminster seems hell-bent on dumping it on the Clyde – it would appear at any cost.

"Trident renewal has always been utterly indefensible – and these costs will almost certainly only go one way from here – even further up.’’

The SNP and Scottish Greens have maintained a long-standing opposition to Trident, and at its autumn conference last year Scottish Labour adopted a policy to oppose renewal. In November, a majority of MSPs in Holyrood also voted against it.

In its strategic defence and security review at the end of last year, the Westminster Government announced an increase from £25bn in the estimated cost of four new Trident submarines to £31bn, with an additional £10bn to cover overspends.

The CND estimate is also substantially higher than a previous calculation made by Crispin Blunt, Conservative chairman of the Commons foreign affairs committee. He worked out on the basis of parliamentary answers that a new Trident system would cost £167bn over a 30-year lifespan.

CND’s figure emerged days after a survivor of the Hiroshima bomb travelled to Scotland as part of her campaign against nuclear weapons.

Setsuko Thurlow, 84, was 13 when American forces dropped an atomic bomb on her Japanese home city in August 1945, towards the end of the Second World War.

The building she was in, a mile from the blast site, was destroyed and she fled to the hills outside the city. She and two other girls tried to comfort the injured and dying, soaking their blouses in a stream and holding them to their lips so they could give them water.

Thurlow met SNP MSP Bill Kidd, co-president of the international group Parliamentarians for Nuclear Non-Proliferation and Disarmament (PNND), and new Scottish Green MSP Mark Ruskell in Edinburgh. Last night the Ministry of Defence disputed CND’s estimate.

Minister for Defence Procurement Philip Dunne said: “This is more fiction dressed up as fact from known opponents of the strategic deterrent. We do not recognise these figures.

“We have been clear on the cost estimates published on the successor submarine. We are replacing the submarines and that cost equates to 20 pence in every £100 of annual government spending. The in-service costs remain unchanged – around six per cent of the annual defence budget.”