British MPs are set to vote tonight on whether to renew the Trident nuclear deterrent, in a debate expected to highlight deep divisions in the Labour Party.
Jeremy Corbyn is strongly opposed to Trident but has given his MPs a free vote on the issue.
According to reports, more than half are expected to break ranks and side with the government.
The SNP, which is strongly opposed to Trident, has called on Prime Minister Theresa May to delay the parliamentary debate until the full cost is known.
In a statement, the SNP's leader in Westminster Angus Robertson said the decision needed "proper scrutiny".
"Trident is an immoral, obscene and redundant weapons system - and the decision on whether to renew it is one of the most important votes this parliament will ever take," he said.
His misgivings were echoed by Brendan O'Hara, the MP for Argyll and Bute and the SNP's defence spokesman.
He said: "We have come here with a mandate from our country, from the Scottish government, from the Scottish parliament the Scottish churches and great swathes of civic society.
"Most political parties have said we do want Trident. Scotland has said we do not want Trident yet we are having Trident thrust upon us by a Tory government that we didn't elect and that we do not want."
Jeremy Corbyn speaks at a Stop Trident protest rally in London in February 2016 | Photo: PA Images
Local response
The Trident nuclear programme consists of four Vanguard-class submarines armed with Trident II D-5 ballistic missiles.
They are operated by the Royal Navy and based at Clyde Naval Base, commonly known as Faslane, on the west coast of Scotland.
The government estimates its replacement would cost £31bn over 20 years.
People living next to the base in the town of Helensburgh will be watching the vote closely.
Kathleen Owen and her husband run a thriving pet shop and like most local businesses rely on trade from the thousands of personnel who work there.
She told Sky News "The base is key to the economic viability of Helensburgh. If it closed it would have a detrimental effect.
"Lots of people who've worked on the base have also retired here and still live in the town. Everyone has a connection to the base."
But residents of a peace camp close to Faslane which has been occupied by protesters for almost 35 years would like to see the base shut down.
One, Iona Soper, said: "If you want the nuclear weapons you are voting for down south, you have them down south.
"We're not voting for them up here - we've elected a party which is very anti-nuclear."
