THERESA May today faces growing pressure over Britain’s nuclear deterrent as a new poll suggests waning public support for Trident.

In the first days of Mrs May’s tenure as Prime Minister, Conservative MPs are expected to overwhelmingly support the renewal of Trident in a Commons vote.

A new UK-wide poll for The Herald shows that just 45 per cent of British people are in favour of renewing the project.

Read more: Scots MPs line up against Trident ahead of key vote

Just over a quarter, 27.5 per cent, oppose the move, and almost the same number, 27.9 per cent, say that they don't know.

A similar poll carried out by ComRes in January suggested 54 per cent backed Trident renewal, while 22 per cent opposed.

Next week MPs will be asked to support a new like-for-like replacement of the current four submarine system.

Mrs May, who officially becomes PM today, advocated a speedy vote earlier this month, saying it would be “sheer madness” to give up Trident in the face of threats from Russia and North Korea

A Conservative source said the party would be delivering one of its manifesto commitments with the vote.

But the SNP has accused ministers of planning to waste hundreds of billions of pounds on a “wasteful and reckless” system.

A potential second independence referendum has also raised real questions over the future home of Trident.

The SNP has said that an independent Scotland would not accept nuclear weapons on its soil.

The Church of Scotland yesterday condemned the rush to hold the vote, announced at the weekend, saying it had opposed Trident for more than 30 years.

In a joint statement eight Catholic bishops in Scotland also called on the UK to take "decisive and courageous steps" towards eliminating nuclear weapons.

Read more: Nicola Sturgeon condemns Trident and House of Lords as 'twin relics'

"Lives are being lost now because money that could be spent on the needy and the poor is tied up in nuclear arsenals," they said.

The group also said that they endorsed the words of Pope Francis: 'Spending on nuclear weapons squanders the wealth of nations.'

The BMG poll also found that most of those aged 55 or over were in favour of renewing Trident.

Twice as many women as man said that they don’t know, 37 per cent versus 18 per cent.

Overall, most men, 52 per cent. say they thought Trident should be replaced.

There was also a clear majority in favour among Tories and Ukip supporters, 66 per cent and 62 per cent respectively.

Most of Labour’s current supporters oppose the idea, with 34 per cent for, 42 per cent against and 24 per cent don't know.

Read more: Unite reaffirms backing for workers involved in Trident programme

But those who voted for Labour in 2015 are more in favour, with 40 per cent for, 38 per cent against and 22 per cent don't know.

Michael Turner. from BMG, said: "The Trident question neatly demonstrates just how much the Labour party has changed since its electoral slump in 2015 and the subsequent election of Jeremy Corbyn as leader.

"Our polling shows that Labour’s support, pre-Corbyn, would have voted for the renewal of trident, whereas Labour’s supporters today, are mostly against doing so."

The Conservatives, who have a slim Commons majority, are expected to win the vote comfortably.

The motion is expected to be supported by a number of Labour MPs, who fear their party is losing credibility on defence issues under Mr Corbyn.

MPs will be lobbied today by campaigners around the country, including from Scotland, over the vote.

At the weekend demonstrations will be held in towns and cities across Scotland including Glasgow, Edinburgh, Aberdeen, East Kilbride, Dundee, Stirling, Ayr, Biggar, Largs and Wick.

SNP Defence spokesperson Brendan O'Hara said: “It is particularly galling that the UK government plans to dump this nuclear arsenal on the Clyde for the next fifty years despite overwhelming opposition from the Scottish people, as well as the Scottish Government and Parliament.

“The comments from leading bishops across the country highlight the breadth and strength of opposition in Scotland to Trident nuclear weapons and the UK government's reckless plan to waste billions on their renewal.

"It is obscene that Theresa May thinks the priority at a time of Tory austerity and economic uncertainty following the EU referendum is to spend billions on outdated nuclear weapons that we do not want, do not need, and could never use.

“The SNP is clear in our position - we will be united in voting against new Trident nuclear weapons and we call on MPs of other parties to do the same."

David Cameron discussed Trident renewal at the last meeting of his cabinet yesterday (TUES).

No 10 said that he had recounted "that one of his more memorable visits had been when he was being winched into a submarine off the coast of Scotland”, adding that the nuclear deterrent “underlined Britain’s ongoing place in the world and that we remain an outward-looking nation”.

Ministers unanimously supported having four submarines to deliver continuous at-sea deterrence and the need to keep a tight rein on the costs of replacing Trident.

BMG asked more than 1,000 UK adults between June 10 and 15.