NICOLA Sturgeon has branded the Scottish Secretary disgraceful for threatening to reverse the decision to keep open BAE's Clyde shipyards and close Portsmouth in the event of a pro-independence vote.

Ms Sturgeon also said LibDem Alistair Carmichael's behaviour since the BAE announcement to close the Portsmouth yard and keep Govan and Scotstoun open, albeit with more than 800 job losses, has been "shameful".

The SNP deputy leader said: "[Mr Carmichael's] job is to stand up for Scottish interests but he is quoted in the Portsmouth press talking about taking jobs from Scotland. That is disgraceful."

Speaking after visits to the Scotstoun and Govan yards to speak to management and trade unions, Mr Carmichael said: "The difference between the UK and Scottish Governments on this issue is we understand how the procurement process works while they have only offered up a series of ifs, buts and maybes on the future of the industry under independence."

During a visit to Scotland yesterday, Labour leader Ed Miliband refused to rule out reversing the yards decision in the event of Scotland becoming independent.

He said the uncertainty was "caused by a party that wants to split away from the United Kingdom", adding: "The best way, not just on naval capacity and shipbuilding, but on currency and economic policy, is for Scotland to stay part of the UK."

Scottish Labour leader Johann Lamont accused the SNP Government of having no plan for diversifying Clyde work.

But Ms Sturgeon said an ­independent Scotland could emulate Norway, which built 100 ships at more than 40 yards last year, and ridiculed the notion the Clyde yards would lose the crucial contracts to build the next generation of Type-26 frigate if Scots voted in favour of independence.

The two opponents, who ­represent neighbouring constituencies dominated by shipyard jobs, traded bitter exchanges after initially expressing their concerns for the 835 jobs lost in Scotland and 940 at Portsmouth.

Ms Lamont told her: "The ­reality is the UK has not built a warship outside the UK since the Second World War. Can [Ms ­Sturgeon] explain to my constituents and hers who work on the Clyde what will happen to their jobs should there be a Yes vote?"

Ms Sturgeon, who will visit the Clyde with Finance Secretary John Swinney today, said: "This is a question about what happens after Scotland has democratically voted for independence,and surely she is not going to seek to blackmail Scottish shipyards?"

Ms Lamont responded: "Once that vote is taken next year, we have no influence over what a UK Government would do because we are not in it."

Ms Sturgeon insisted: "Our shipbuilding industry is being downsized before our very eyes. The threat to defence jobs in Scotland is not independence, it's Westminster."

She said both UK Defence ­Secretary Philip Hammond and BAE had described Glasgow as the "best place to build those ships, end of story", adding: "The Clyde is now not only the best place to build these ships, it is the only place in the UK to build these ships."

She also cited an announcement earlier this year by the UK Government it would be collaborating with Australia on the next generation of frigates, and the suggestion there could be similar deals with Malaysia, New Zealand and Turkey.

Ms Sturgeon asked the Scottish Labour leader to explain why the UK Government would consider a collaboration with a country 10,000 miles but not one with another country on the same island.

Conservative leader Ruth Davidson called on the Scottish Government to support the upgrades needed for the Clyde to compete for the Type-26 warships.

Liberal Democrat leader Willie Rennie accused Ms Sturgeon of inconsistency by previously ­calling for UK vessels to be built in-house by the UK and now ­insisting the rest of the UK could contract out the work to Scotland even in the event of independence.