TRIDENT will be renewed no matter what Labour’s policy, the shadow Scottish Secretary has said, despite his party leader vowing to work with the SNP to oppose a replacement.

Ian Murray, who opposes Trident, said the Conservative majority at Westminster meant a replacement for the ageing weapons system “will happen”.

Labour is braced for a ferocious debate on Trident at its annual party conference which opens in Brighton this weekend.

New leader Jeremy Corbyn is vehemently opposed to nuclear weapons, but his party currently backs renewing the UK’s programme.

He said last night he would work with the SNP to oppose the renewal and would like to see nuclear defence jobs at Faslane transferred to other forms of “high-value engineering”.

He added: “I think Trident should go. I do not believe that it is a form of defence. I do not believe it is something that anyone in their proper mind would ever want to use, so I ask the question is it really sensible to commit such a vast proportion of our assets - £100bn over 25 years - to this when we could be spending it on developing our industrial infrastructure?

“In the House of Commons, I was chair of the CND group and one of the vice chairs is from the SNP and yes we will be voting with them on this, or they will be voting with us, whichever way you want to put it.”

But in an interview with The Herald, Mr Murray said Trident renewal "will happen".

He also argued that the Westminster arithmetic meant the issue could not be used to justify a second independence referendum.

The decision had effectively already been taken, he suggested, and could not be seen as a “significant” change.

Alex Salmond has suggested that potential triggers for another referendum could include Trident renewal.

But SNP leader Nicola Sturgeon has said that “something significant” would have to change for her party to back another vote.

Mr Murray, who last year broke ranks to oppose replacing the deterrent, said: “Trident renewal will happen.

“The decision is going to be made next year and the Conservatives have a majority - there is an absolute Conservative majority.”

Mr Murray said that one of the “most controversial” of the Tory government‘s plans – to cut tax credits –passed through the Commons “with a comfortable majority”.

“Even though there was a (Tory) backbench rebellion on the tax credits, the backbenchers decided not to follow that through and vote against the government.

“So this is incredibly difficult, there is no getting away from that.

“Without having the numbers it will be almost impossible to defeat the government on what will be fundamental questions.

“We will defeat the government on minor questions, as we have done already, but this (Trident) is a fundamental issue.”

On another independence referendum, he argued: “It is not a ‘significant change’. It is the status quo.”

The SNP is opposed to nuclear weapons.

But divisions within Labour are expected to come to the fore at the first party conference since Mr Corbyn was elected leader.

Some MPs like the veteran left-winger are utterly opposed to the UK retaining nuclear weapons.

Others believe they are necessary for national security.

Some unions also oppose scrapping Trident because of the number of jobs based at its Faslane home.

Both the new Labour deputy leader Tom Watson and the shadow foreign secretary Hilary Benn have said in recent weeks that the party supports keeping Trident.

But Mr Corbyn has signalled that he will see his party conference as much more important to Labour’s policy-making process than some of his predecessors.

Delegates are due to vote tomorrow on whether or not to select a proposed motion on Trident.

Mr Corbyn said yesterday: “I think it’s going to be discussed and I’m sure the majority of delegates both in the union section and the constituency section will want it discussed.”

Scottish Labour is due to debate nuclear weapons at its annual conference later this year, in a move that could pave the way for the party north of the border to oppose Trident renewal.

The issue is reserved to Westminster.

SNP defence spokesman Brendan O'Hara said: "If Mr Corbyn and Labour have any hope of being treated seriously by the vast majority of voters in Scotland, then he must get party support in his commitment to backing the SNP's plan to scrap the replacement of Trident.

"Indeed, if he cannot then many more people in Scotland are likely to conclude that independence is the only way to ensure getting rid of Trident."

The Conservatives currently have a small working majority of just 16 in the House of Commons.

But the Democratic Unionist Party (DUP), which has another 8 MPs at Westminster, has also said that it supports Trident renewal.

The Tories are committed to a like-for-like replacement of the nuclear deterrent.

During the General Election the Tory Defence Secretary Michael Fallon was criticised after suggesting that the then Labour leader Ed Miliband would stab the country “in the back” on Trident renewal – just as he had done his brother David when he stood against him in 2010.