Moving the UK's nuclear deterrent out of an independent Scotland is not impossible and would probably cost far less than the tens of billions of pounds previously predicted, experts have suggested.
Relocating Trident in the event of Scottish independence would be feasible, although it could take more than a decade and spark significant local opposition, a new paper from the Royal United Services Institute (Rusi) military think tank has found.
But the paper, published tomorrow suggests that recreating the nuclear facilities outside Scotland would add between £2.5-3.5 billion to the cost of maintaining a nuclear-armed fleet, plus the cost of acquiring and clearing land - but would be far less than a previously-predicted £20-25 billion.
Relocation, Relocation, Relocation: Could the UK's Nuclear Forces be Moved after Scottish Independence? looks at the financial and political hurdles of moving Trident if Scotland becomes independent.
Coming just weeks before the independence referendum, it addresses fears over the future of Britain's nuclear forces if Scotland is no longer a part of the United Kingdom.
Former cabinet minister Lord Forsyth has previously warned that the UK c ould be forced to give up its nuclear deterrent in the event of a Yes vote, saying separation could have a major impact on the defence of both countries.
The submarines carrying the UK's Trident nuclear warheads currently operate from the Faslane naval base on the Clyde and there are concerns over how they can be relocated.
But the paper, by Rusi research analyst Hugh Chalmers and Rusi research director Malcolm Chalmers, says relocating Trident out of Scotland would be both financially and technically feasible.
They estimate that recreating the facilities outside Scotland would add £2.5 to £3.5 billion (at 2012/13 prices) to the cost of maintaining a nuclear-armed fleet, plus the cost of acquiring and clearing the land and costs of moving people and material around, but it is very unlikely to cost "tens of billions" cited elsewhere.
But it would take more than a decade to recreate the facilities, rather than the four years to which the SNP is currently committed, the authors said.
Hugh Chalmers said the research contrasts with an "unlikely consensus" between proponents and opponents of Scottish independence that it would be impossible to relocate nuclear forces elsewhere.
"And therefore if you can't base them in Scotland, you can't base them in the UK, and you can't base them elsewhere, you would have to disarm," he said.
But he said nuclear weapons still play a key role in defence and foreign policy, creating concerns over the effect that a Yes vote would have.
If the question mark over Trident's future could be answered, it would help untangle a difficult issue surrounding Scottish independence, he said.
"W hen people start considering options for relocations it's only natural to assume that it would be quite expensive and very difficult and that is certainly the case. But importantly it is not impossible.
"We estimate that essentially the net costs of relocating could actually be £2.5-3.5 billion at 2012 prices, rather than the tens of billions or even £20 billion that has been put forward so far."
But he said it would take a long time, and was unlikely to be completed by a target date of 2020, and a more "natural timeframe" would be linked to the entry of a new generation of nuclear-armed submarines, currently anticipated to start in 2028.
"It may be possible to deactivate Trident by that point and have it out of Scotland but it's unlikely we would have been able to have it up and running in a new location by that point.
"The Scottish government has acknowledged that if they were to become independent there would be a period of time where the UK would be basing its nuclear forces in an independent country. The UK would be the first country to ever do this."
Mr Chalmers said the new paper showed the possibility of a "space for a friendly and amicable settlement" over Trident in the event of independence.
He added: " Effectively this is a key aspect of any negotiations that will emerge after a yes vote.
"This will be a very, very important issue. If both Scotland and the UK can show that they can come to some sort of amicable arrangement then that untangles a very knotty issue.
"We are trying to essentially dispel the myth that relocating Trident out of Scotland is impossible and in doing so create some space allowing an amicable settlement to be reached in the event of a yes vote."
A Scottish Government spokeswoman said: " Trident is opposed by the people and Parliament of Scotland. The Scottish Government position is that Trident should be removed from an independent Scotland by 2020 - before we are hit with a share of the further £100 billion in lifetime costs, at 2012 prices, which are estimated for its replacement.
"We will also propose a constitutional prohibition on nuclear weapons being based in Scotland, ensuring they would never return.
"As the Trident Commission reported, when spending reaches its peak in the next decade, taxpayers will be spending nearly £4 billion a year on nuclear weapons at 2012 prices - that is unacceptable when there are so many other pressing needs which public money is needed for.
"As Rusi's paper shows, the UK Government has choices on what it decides to do with its nuclear weapons following their removal from an independent Scotland, including of course the potential to reconsider the possession and planned renewal of Trident.
"The Scottish Government will work responsibly with the Government in Westminster in securing the speediest safe withdrawal of Trident from an independent Scotland. We look forward to the opportunity to discuss these arrangements with the UK Government following a vote for independence."
A Ministry of Defence spokeswoman said: " The nuclear deterrent is the ultimate guarantor of our nation's security and no alternative would be as effective at deterring threats now or in the future. There are no plans to move Trident from Her Majesty's Naval Base Clyde and unilateral disarmament is not an option.
"We are not planning for Scottish independence and as such it is difficult to estimate the total costs, or how long it would take, to replicate the facilities at Faslane, but it would likely cost taxpayers billions of pounds and take many years."
"HM Naval Base Clyde is the largest single employment site in Scotland, home to 6,700 jobs and set to increase to 8,200 jobs. The Scottish Government needs to be clear-sighted and honest about the risk to the local economy that their policy presents."
Jackie Baillie, Labour MSP for Dumbarton, said: "Once again we see the experts saying one thing, and Alex Salmond another.
"Alex Salmond claimed that a separate Scotland would remove Trident within four years. This expert, impartial report shows he was wrong.
"If we cannot trust what he says on this why should we believe him on currency or our place in the EU?
"Employers at Faslane say that losing Trident would mean losing jobs, and we cannot trust anything the nationalists say about keeping jobs at Faslane when they can't answer the basic questions.
"Like everything else in his campaign to break up the United Kingdom, the details are based on guesswork.
"Time is running out for the nationalists to be honest with the people of Scotland about what separation would mean for them. They should start by outlining their Plan B on currency."
SNP Westminster Leader and defence spokesperson Angus Robertson said: "This report puts to bed some of the ridiculous claims being put forward by the No campaign, including UK government ministers, on removing Trident from Scotland.
"We are clear, however, that getting rid of Trident from Scotland by 2020 is a perfectly reasonable timescale - indeed, Westminster's own Scottish Affairs Committee reported that Trident could be 'removed within months'.
"The new generation of Trident nuclear weapons to be dumped on the Clyde is to cost over £100 billion, with annual spending rising to £4 billion a year in the next decade.
"That's an obscene waste of money on obscene, unusable nuclear weapons which the vast majority of Scots do not want - when with a Yes vote Scotland's share of this money could be used instead for childcare, nurses, teachers, schools and hospitals.
"The UK Parliament's Trident obsession highlights the democratic deficit that Scotland faces under Westminster control.
"It is ludicrous that we are wasting billions of pounds of taxpayers' money on Trident - a Yes vote means it will instead be used to build a fairer society and stronger economy, with more opportunities for all."