Garry Graham, Prospect deputy general secretary, said:
"We have a very well respected and highly skilled workforce at Rosyth and Devonport which has been facing job cuts and uncertainty while the government dithers over building and decommissioning projects.
"We are at risk of permanently losing skills and jobs which could easily be safeguarded if we just got on with the job of decommissioning these vessels. We also have more subs about to come out of service and we simply do not have space to put them anywhere.
“We have the ability to carry out the decommissioning work right now but the MoD and the government seem content instead to continue to throw money away by merely storing these vessels - it is putting our reputation as a responsible nuclear power at risk.
“Our submarine fleet is key to the defence of the UK. Fundamental to the credibility and public confidence of our future submarine strategy is a clear programme for the safe and expeditious decommissioning of vessels as they reach the end of their in service life span. This government talks tough on defence but fails to provide the resources needed to meet the threats we face in an increasingly uncertain world.
"There is an opportunity here for the government to create and secure high value jobs both in ship building, and making use of existing skills in the civil decommissioning sector. It would have the added bonus in Rosyth of safeguarding the skills and infrastructure required to maintain the magnificent HMS Queen Elizabeth in her home port.
“It's time they got on with it and gave our workforce the vote of confidence it deserves.”