The Chancellor George Osborne will fly into Faslane today to announce an extra £500 million for the home of the UK’s nuclear deterrent and accusations he is pre-empting a Commons vote on its renewal.

Mr Osborne will say that the money will secure 6,700 jobs and create thousands more.

But opponents have accused the Chancellor of spending money that they claim effectively paves the way for the replacement of Britain's nuclear deterrent before MPs gets to decide.

Local SNP MP Brendan O’Hara said: “This so-called investment in Faslane will directly support the deployment of Trident submarines."

Mr Osborne was “essentially pre-empting a vote and actual decision on renewal of Trident”, he said.

The new money is for work to ensure Faslane retains its position as a world leading naval base, the Treasury said.

More than £500 million will be spent on ship lifts, sea walls, jetties and other major projects.

The work is expected to start in 2017 and will take a decade to complete.

Treasury sources said that not all the new jobs created would be at the base, with a significant number in the UK-wide supply chain.

They said that the move to upgrade Faslane followed the Chancellor’s surprise announcement in his Summer Budget earlier this year that the UK would commit to the NATO commitment to spending at least two per cent of GDP on defence.

By the end of this decade Faslane is due to become the Royal Navy’s ‘Submarine Centre of Specialisation’.

It currently has around 6,700 military and civilian staff and contractors, but this is forecast to rise to about 8,200 by 2022.

Speaking in Faslane, the Chancellor will say that the extra £500m “demonstrates the UK Government’s commitment to investing in the infrastructure and capability to ensure that Faslane remains the centre of UK submarine operations for the next generation.

“I’m proud to say that this government continues to recognise that our brave Armed Forces across Britain have always been resolute in defence of liberty and the promotion of stability around the world."

He will add: “There will be thousands more jobs right here in Faslane, as well as across the UK supply chain. Across Scotland, around 12,600 people work in defence and my defence spending commitments will secure these jobs and provide huge opportunities for defence, security and technology companies all over the UK.”

The Campaign for Nuclear Disarmament described Mr Osborne’s trip as “disrespectful”.

Earlier this year whistle-blower William McNeilly warned of safety fears with the Trident system.

John Ainslie, co-ordinator for the Scottish SND, said: “George Osborne’s presence at Faslane will do nothing to reassure the Scottish public that everything is safe at Britain’s nuclear base.

“We know from the revelations of William McNeilly that Trident is a ‘disaster waiting to happen’.

"The Chancellor is about to commit billions of pounds to renewing Trident.

“If he had any respect for Scotland he would be coming here to announce that Trident would be scrapped. Sadly, I suspect that this is not the case.”

Mr O’Hara added of the Chancellor: “I hope when he is here he gets the message loud and clear that Scotland does not want [the UK] to spend £100 billion on Trident replacement or renewal.

“Fifty-seven of the 59 Scottish MPs are implacably opposed to Trident renewal and the people of Scotland are clearly opposed to the policy and I think he will hear that message.”

Willie Rennie, the Scottish Liberal Democrat leader, hit out at the SNP saying that “nationalists would be outraged if UK ministers never bothered to turn up” to announce plans that will result in extra jobs.

Mr Rennie, whose party has argued against a like-for-like replacement for Trident of the kind favoured by the Tories, said: "Faslane is set to be the sole submarine base for the whole UK. Thousands of jobs are attached to this move. It is right for UK ministers to visit. In fact nationalists would be outraged if UK ministers never bothered to turn up. The nats should make up their mind."