The SNP have accused the Defence Secretary of being obsessed with weapons of mass destruction after he announced plans to personally cut steel on the first of a new generation of nuclear submarines.

Sir Michael Fallon will carry out the symbolic act today in Barrow-in-Furness, Cumbria, where the vessels will be built, kicking off the process to replace Trident.

Yesterday he told Tory activists at the party's annual conference in Birmingham that the scheme would benefit businesses from the north of Scotland to the south of England.

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And he accused Labour, whose leader Jeremy Corbyn opposes nuclear weapons, of “waving the white flag”.

Sir Michael said: “I will be cutting steel on the first new Successor Trident submarine – a billion-pound investment that will benefit businesses from Barrow to Berkshire, from the North of Scotland to Tyneside.

“Contrast that with the Labour Party, while we are getting on with the Successor programme they can’t even agree on a successor to Jeremy Corbyn.

“Instead, they’ve just re-elected a Leader who wants to scrap our nuclear weapons, leave Nato, and talk to terrorists.

“Let me tell you, waving a white flag won’t keep us safe.”

The House of Commons voted to replace Trident earlier this year.

But only the vast majority of Scottish MP opposed renewal.

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Brendan O’Hara, the SNP’s defence spokesman, said: "58 of Scotland’s 59 MPs voted against this awful project’s renewal. The plunge in sterling because of the Tories’ total lack of any Brexit plan - is adding to the already astronomical costs of Trident.

"This means conventional defence spending – already cut to the bone – is squeezed even more because of their utter incompetence.

"The Tories are obsessed with their nuclear weapons of mass destruction – it seems - at any cost and at any damage to our defence.’’

Shadow defence secretary Clive Lewis accused Sir Michael of a "smokescreen", designed to draw attention away from “the Tories legacy of failure on defence".

He added: "The reality is their devastating cuts since 2010 have weakened and demoralised our Armed Forces, leaving them poorly-equipped, over-stretched, under-paid and too often living in squalid conditions.”

He too accused the Tories of an "obsession", this time with cost-cutting.

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“(This) means they are not even using British steel to build our ships and vehicles,” he said.

Campaigners claim that over the lifespan of a new generation of nuclear weapons the cost to the taxpayer will top £200 billion.

CND general secretary Kate Hudson said: “This decision is not in Britain’s interest.

"Cutting steel tomorrow means wasting £205 bn on a nuclear weapons system that will do nothing to address the security threats we face.

"Every billion spent on Trident is a billion that isn’t spent on real defence and security.”

She called for a policy designed for the 21st Century that could “tackle terrorism, climate change, cyber warfare and global pandemics” instead of a “Cold War mentality”.