Voting for independence means putting thousands of jobs in the defence and shipbuilding industries in Scotland at risk, shadow defence secretary Vernon Coaker said during a visit to the Rosyth shipyard.
Lucrative UK contracts such as building aircraft carriers for the Royal Navy, which are estimated to have brought about £300m of sub-contracts to Scottish companies, will most likely be moved elsewhere if Scotland decides to break away from the Union.
"The jobs of thousands of Scots in our defence industry are secured by being part of the UK. They play a critical role in supporting our armed forces and helping to keep us all safe and secure,” Coaker said.
"The UK Government has never awarded a contract for complex warships outside of the UK. The idea that somehow everything would carry on as it is just because Alex Salmond says so simply isn't credible."
Alongside shipbuilding jobs on the Clyde, there are thousands of Scottish defence jobs across the country in industry, as well as employment from bases at Kinloss, Lossiemouth, and from Faslane to South Uist.
Anas Sarwar, Scottish Labour's deputy leader, commented: "We know the SNP will say and do anything to win the vote, setting aside the reality of life in an independent Scotland.
"The truth is that being part of the UK is good for Scottish jobs but a Yes vote puts those jobs at risk."