A Scottish firm has won a £330m sub-contract to build periscopes for a new fleet of nuclear submarines – while a defence minister said she would be “utterly astonished” if the contentious Trident system was scrapped following a review.

BAE has handed Glasgow-based Thales UK the sub-contract to produce the next generation of periscopes and sonar systems to be used by four new Dreadnought nuclear submarines.

The SNP has repeatedly called for the weapons system - based on the Clyde - to be scrapped, with First Minister Nicola Sturgeon describing it as “immoral” and “a massive waste of money”.

The £330m combat system will be developed and manufactured in Govan while the new Dreadnoughts will enter service at Faslane in the 2030s.

Defence minister Annabel Goldie welcomed the new sub-contract and backed the Trident system, which is subject to a review.

READ MORE: Analysis: settling the Trident controversy could take a generation to resolve

Speaking on the BBC’s Good Morning Scotland, she said: “The review will have to take place and come to its conclusions but I would be utterly astonished if there was any suggestion that we should reconsider that.

“The success of the deterrent is obvious. It is an essential part of our global alliances not least in Nato, where remember we are not just the biggest defence spender in Europe, we are the second-biggest defence spender in Nato.

“That deterrent is an important component of stability throughout the global territory.”

She voiced support for the policy review, describing it as an “excellent opportunity to establish the course of travel for the next 30 to 50 years”.

She added: “The deterrent has always been and always will be contentious.

“But I would point out two things - that (the UK) Parliament voted overwhelmingly in 2016 to continue with the deterrent and the interesting thing about a deterrent is, its success is actually that you don’t have to use it.

“Many people find that a little difficult to grasp but if you get to the point where you are having to use something in a conflict situation to react, then it’s not been a deterrent.

READ MORE: How an independent Scotland could remove Trident

“In fact, mercifully for 60 years we have enjoyed nuclear peace and that’s why the deterrent element is so important.”

Baroness Goldie said there are “clearly significant opportunities for firms north of the board” with Scotland to become the single home of the entire Royal Navy submarine fleet later this year.

She added: “This sub-contract win by Thales clearly demonstrates the importance of the £31 billion Dreadnought programme to UK and Scottish industry.

“Indeed Thales, formally Barr and Stroud, and their Glasgow-based engineers have supplied all of the Royal Navy’s periscope, and now optronic mast, needs for over 100 years. That is a relationship we prize.”

The sonar system will be developed at the Thales sites in Somerset and Cheshire. The contract will create 170 jobs and secure 350 more across the UK, including 35 in Glasgow.

Thales, which has been based in Govan since 1917, has been a trusted Continuous at-Sea Deterrence (CASD) partner with the MOD and Navy since the first operation in 1969. It directly employs more than 7,000 people in the UK across ten sites.

Thales Chief Executive Victor Chavez said: “Thales is immensely proud of our contribution to the Continuous at-Sea Deterrent over the last 50 years.

“This announcement represents a £333m investment in world-class sonar and optronics systems; providing the battle-winning edge for the Royal Navy.

“Having supported the deterrent since its inception, and with over a century of supplying periscopes to the Royal Navy, I am proud that our engineers continue to deliver cutting edge innovative technology at sites across the UK.”

SNP MSP Bill Kidd, said: “The Scottish Parliament and the people of Scotland firmly reject the hosting of weapons of mass destruction on Scottish soil, and Westminster need to heed those calls.

 “It’s time for the UK government to end their ridiculous love affair with nuclear weapons, and follow in Scotland’s footsteps by helping creating a green jobs boom north or the border through investment in renewable technology. 

 “The SNP has always been clear. When Scotland becomes an independent country, all nuclear weapons will be removed as quickly and safely as possible."

In December, Nato general secretary Jens Stoltenberg said Britain’s Trident system is “important”.

He said: “Britain is a highly valued member of Nato for many reasons.

“You spend more than two per cent on defence, you provide a lot of valuable, high-end capabilities, and you have shown again and again you are willing to deploy when needed.

“Part of the UK contribution to Nato is of course the UK nuclear weapons - the nuclear deterrent - which contributes to the overall nuclear deterrent of Nato, which is something that is important for Nato.”