Media playback is unsupported on your device Media caption One defence worker in Glasgow confronted Defence Secretary Philip Hammond over "threatening" jobs, as Allan Little reports

Defence Secretary Philip Hammond has predicted that a vote for Scottish independence would put defence jobs at risk.

Speaking to defence workers in Glasgow, he claimed the UK's shared defence forces provide benefits of scale.

SNP defence spokesman Angus Robertson said Mr Hammond was spreading "myths and misinformation" in Scotland.

The SNP has said that, in the event of a "yes" vote, all existing military bases in Scotland would be retained.

It has insisted, however, that nuclear submarines would be removed from their base on the Clyde.

Mr Hammond said: "Successive UK governments have deliberately chosen to sustain our sovereign capability - albeit at a financial premium.

"As a result no complex warships for the Royal Navy have been procured from outside the UK since the start of the 20th Century - except during the two world wars.

"Today that policy and the Royal Navy's scale delivers billions of pounds of investment and sustains thousands of Scottish jobs directly and indirectly, and I believe it is neither in Scotland's interest nor the rest of the United Kingdom's to put that at risk."

Mr Hammond also claimed the government of an independent Scotland would have to pay part of the cost of removing the Trident base from the Clyde.

He said: "If we did have to move the Trident nuclear deterrent from Faslane as a result of the negotiations that happen after any independence vote, it would take about 10 years at least to design and construct a suitable alternative site. It would cost a very large amount of money.

"I can't say precisely how much, but it would be many billions of pounds. And that timescale and that cost would have to be taken into account within the overall negotiations."

Asked if an independent Scotland would pay part of these costs, he replied: "Absolutely, it would pay part of that bill. Those costs would have to be taken into account as part of the overall settlement."

Defence co-operation

Commenting after the defence secretary's speech, the SNP's leader in Westminster and defence spokesman Angus Robertson said: "Another day, another scare story.

"Scotland is a maritime nation but we have no maritime patrol aircraft. They used to be based here until they were all scrapped by the UK government.

Media playback is unsupported on your device Media caption Angus Robertson, leader of the SNP in Westminster, says the UK government does not take Yes plans for defence seriously

"We are a maritime nation but we have no maritime naval patrol vessels.

"Independence gives us the advantage of being able to make better decisions - so we have those maritime capabilities, so we have the things that we need as opposed to the things that we don't want, like Trident."

'Threads of a rope'

Mr Hammond's speech followed comments by the first sea lord about the prospect of Scottish independence.

Admiral Sir George Zambellas told the BBC that it would be like "pulling threads out of rope".

Sir George said: "I believe very strongly that, for a premier league navy, respected around the world, with a big responsibility, for us to be divided would be less efficient for both the UK and Scotland.

"The nature of our military construct, infrastructure, basing, people, equipment and the families who support a hard-pressed navy, all of those add up to a construct which doesn't bear dividing its efficiency, and my job is to provide the navy as efficiently as I can.

"The way we do business means that if you try to pull some threads out of the rope it's much less efficient, and that applies particularly to the navy because it's so hard-pressed.

But Col 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.

He told the BBC Scottish forces would have a regional, not global, focus.

He said: "Scotland would be more than capable of running its own armed forces should the country become independent.

"We shouldn't imagine that those armed forces would be a microcosm of the UK's armed forces - not just 10% of the UK inventory if you like.

"It would be something much more modest with a different focus."

The Scottish independence referendum is scheduled for September 18.