ALEX Salmond has given a clear guarantee that the Royal Navy would continue to build warships in an independent Scotland.
The First Minister's stance puts him at odds with Defence Secretary Philip Hammond, who made it clear that no such promise could be made.
In a week that has seen the UK Government make a concerted push on the issue of independence and defence, the First Minister used a speech at the STUC in Dundee to hit back.
When asked by shipbuilder Alex Logan from Port Glasgow, Inverclyde, if he could guarantee the shipbuilding industry would continue long-term in Scotland, Mr Salmond replied: "Yes, it will. The Royal Navy will continue to order ships from Scottish yards based on (the fact) that these are the best places to produce these vessels."
The First Minister stressed that diversification would be needed to retain shipbuilding in Scotland at a critical mass but noted that, even with reduced defence expenditure, because Trident would be moved south, the Scottish Government "would be buying more in terms of procurement than we are presently".
In a swipe at the Coalition, he added: "It would, therefore, be ridiculous to try to put up a defence flow barrier and there would be no reason for it whatsoever as it would be cutting off noses to spite faces."
However, in Glasgow at the French defence firm Thales, the Defence Secretary, who pointed out the industry in Scotland employed 12,600 people and generated sales in excess of £1.8 billion, said thousands of these defence jobs would be endangered if Scots voted Yes.
He stressed that the Ministry of Defence bought much of its capability from within Britain, not for reasons of sentimentality, but for strategic control, security and resilience in times of conflict.
He said: "If we were to separate, then the future of the defence industry in Scotland that depends on MoD orders will be put at risk.
"The future of sites such as this would be clearly jeopardised and the assertion by the nationalists that they would generate in Scotland's own defence forces the orders that would keep our shipyards going, that would sustain plants like this, is simply not credible when you look at the numbers."
However, one Thales staff member, Daniel McGee, criticised Mr Hammond's approach, saying: "I feel aggrieved that you've come up here and seem to be quite threatening; that our jobs will go."
The Secretary of State replied that while he was upbeat about the "huge achievements" of the 300-year-old Union, Scots were "entitled to honest answers to questions".
Mr Hammond's remarks came as the First Sea Lord Admiral Sir George Zambellas became the first senior serving officer to voice grave concerns about independence, warning that a Yes vote would damage the very heart of Britain's maritime defence capability.
His intervention followed that from a dozen high-ranking former military chiefs, who said removing Trident from Scotland would cast a "dark shadow" over an independent Scotland's reception on the world stage.
However, Mr Salmond was given a round of applause by STUC delegates when he repeated his commitment to rid Scotland of nuclear weapons.
Meanwhile, his colleague Angus Robertson, the SNP's defence spokesman, claimed Scotland had "already been stripped bare of conventional naval capability by Westminster's cuts".
Earlier, Colonel Stuart Crawford, who has advised the SNP on defence matters, said an independent Scotland would be more than capable of running its own armed forces but it would be "something much more modest with a different focus".
Last night, John Lamont for the Scottish Conservatives said it was stretching credibility for Mr Salmond to suggest Royal Navy warships would continue to be built on the Clyde if Scotland voted to leave the UK.
He said: "The First Minister would rather rely on bluster and assertion than be straight with the people of Scotland."
Meanwhile, Sir Menzies Campbell, for the Scottish Liberal Democrats, said all the evidence showed Scotland was "safer and more secure as part of the UK family" and it was beyond doubt that if existing military capabilities were divided, then "our overall capability will inevitably be diminished".