The cost of replacing Trident has now topped £200 billion, according to campaigners.

The new calculation comes just months after the Ministry of Defence admitted that the price of building new submarines had soared from £25 bn to £31bn.

Read more: Trade union's call to 'back the bomb' puts Labour splits on Trident at heart of election​

Defence chiefs also admitted that they had set aside an extra £10bn in a contingency fund.

The UK Government has consistently refused to put a figure on the overall cost of the decades-long programme to replace the ageing nuclear weapons system on the Clyde.

But the Campaign for Nuclear Disarmament (CND) said its estimate was that the scheme would now cost £205 billion.

Read more: Tories will back Labour members and trade unionists who want Trident renewal, Ruth Davidson says​

Kate Hudson, CND general secretary, said: "For too long the pro-Trident lobby has been in denial about the real cost to our economy of Trident replacement.

"These new calculations, drawn from actual government figures, show that the bill has spiralled beyond all expectations.

"£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.

"The world has moved on since nuclear subs were first designed and procured – politically, economically and technologically and it’s time for our politicians to catch up."

SNP defence spokesman Brendan O’Hara said that the figures showed that the project was "out of control".