Prospect negotiator Richard Hardy, said: “Any investment which creates jobs is to be welcomed, but we will have to see how many of these will be permanent, good quality jobs recruited locally, and how many will simply be short term contracts, filled from across the UK and EU, which last a few years at most.”

The union, which represents engineering, technical and professional grades at Faslane, also remains concerned that the pay and terms and conditions of staff already working at the naval base remain under threat, and that this tempers any enthusiasm among members for the announcement.

“Clearly when you know your employer, whether in the public or private sector, is cutting your pension, and you’ve seen wages, in some cases, not match increases in the cost of living, it’s sometimes difficult to get excited about announcements like this,” added Hardy.

“It’s down to the unions to make sure this inward investment benefits the local economy, and locally-based workers through the creation of high-quality, long-term employment.”