Scotland's shipbuilders would risk losing lucrative Royal Navy contracts if the country split from the UK, the Westminster Government has said.
Defence minister Philip Dunne said Navy warships were unlikely to be built abroad, as Scotland would be classed if it voted for independence in 2014.
His comments came as the Scottish National Party (SNP), none of whose MPs were at defence questions in the Commons, was mocked for wanting to rid Scotland of nuclear weapons but retaining membership of Nato, which has nuclear bombs.
MPs also discussed the coalition's plans to build Type 26 Global Combat Ships, which are estimated to cost £350 million each and are expected to be built in Scotland.
Shadow defence minister Kevan Jones asked if there was a clause in the contract covering an independence vote by Scottish voters, telling the Commons the Clyde had "a long and proud record of building warships for the British Navy".
Mr Dunne said the UK Government believed Scottish electors would vote "No".
He added: "The UK has not built a complex warship outside these shores since the Second World War; we remain committed to using UK industry to build UK warships.
"In the unlikely event that Scotland should decide to separate from the UK, the Scottish defence industry would only be eligible to bid for contracts placed by a future Scottish government, or competed for outside the UK, placed by the UK or other governments. Many UK defence contracts are exempted from procurement rules for national security reasons."
Last weekend, the SNP's annual conference voted to ditch its opposition to being part of Nato - but the party is committed to ousting the Royal Navy's nuclear-armed Vanguard-class submarines from the Faslane base on the Clyde.
Defence minister Andrew Robathan said: "It's almost incredible that a country might wish to join Nato and then say that Nato's assets and armaments would not be allowed to be stationed or pass through its country. It's an interesting dilemma they will have to sort out among themselves. Unfortunately there are none of them here to answer."