Hundreds of skilled jobs at Rosyth Dockyard are to be cut, following the completion of the Royal Navy's new generation of aircraft carriers.
Babcock has confirmed that 250 staff jobs are to be lost at the site in Fife, where around 1,900 core staff are currently employed.
The firm said the cuts are being made following a reduction in work as the £6 billion project for two 65,000-tonne aircraft carriers approaches the finish line.
HMS Queen Elizabeth set sail from Rosyth in June, while her sister ship HMS Prince of Wales is nearing completion and is expected to carry out sea trials in 2019.
The SNP's defence procurement spokesman said the job losses are a "crushing blow" for the workforce.
Babcock said in a statement: "The prospects for Babcock's operations at Rosyth remain good. The last ten years of the Queen Elizabeth Class (QEC) carrier programme has been an outstanding success story.
"Unfortunately, given the one-off nature of this large-scale programme, as the ships begin to be handed over to our customer, we must inevitably reshape our business to remain competitive and take on new challenges, which we firmly believe exist for Rosyth.
"However, medium term opportunities cannot compensate for the 250 or so specific roles and capabilities no longer needed with the slow-down of the QEC work.
"Our employees are our priority throughout this process, we understand how unsettling this news may be and we will work closely with those affected and our trade union representatives through this consultation period to redeploy or relocate as many employees as possible within our wider organisation and support those who wish to take this opportunity to move on."
SNP defence procurement spokesman Douglas Chapman said: "It is a crushing blow for the staff hit by this announcement, particularly at this time of year.
"Only yesterday I asked the Secretary of State for Defence at Westminster what reassurances he can give to workers at Rosyth following the departure of the carriers and if he would visit Rosyth.
"Now - less than 24 hours later- this dreadful news is delivered to dockyard workers.
"It is deeply worrying that these jobs are lost as the UK Government launches their new industrial strategy.
"The Secretary of State said he was incredibly grateful for the amazing work the Rosyth workforce have done on the carriers - but people in my constituency cannot live on a Tory minister's platitudes.
"They need follow-on contracts and deals, and this latest news underlines the importance of continuing the fight for future Type 31e, fleet auxiliary ships and the other contracts to come to Rosyth."
Scottish Liberal Democrat leader Willie Rennie called on the Government to "work harder" to prevent large-scale loss of skilled workers.
"The boom and bust approach in the warship building sector is expensive and wasteful of skills and expertise.
"Although a lot of work was done to smooth out the peaks and troughs of employment for the carriers, the Government must work even harder to prevent the large-scale loss of skilled workers in the future. "