The Coalition source also told The Herald the cost of relocating the nuclear deterrent to England would cost as much as the plan to replace it with a new generation of submarines, some £25 billion.
A mantra for the Coalition has been that prudent planning is an important part of good government, yet when it comes to preparing for the possibility of the biggest constitutional change of all – a break-up of the United Kingdom – and the consequences for Britain's nuclear deterrent, ministers insist there are no specific contingency plans in place.
In June, Nick Harvey, the Armed Forces Minister, appeared before the Commons Scottish Affairs Committee. He was asked by Alan Reid, the Liberal Democrat MP for Argyll and Bute, what contingency planning the Ministry of Defence had undertaken, given the SNP Government had made clear it would want Trident to be removed from Scottish waters as promptly as possible should Scots vote for independence.
Mr Harvey replied: "The UK Government are not making plans for independence - and hence we are not making plans to move the nuclear deterrent or indeed the submarines from HM Naval Base Clyde.
"In the course of our normal work we have all sorts of con-tingency arrangements in place but we have not had any discussion of the sort that you are alluding to, certainly with either the SNP or the Scottish Government."
The senior UK Government source denounced such a lack of contingency planning. He said: "It's a nonsense. Given this will, in the event of a yes vote, be the biggest single item up for negotiation, then there has to be some planning in place but, remarkably, there isn't."
The source explained the lack of contingency planning would mean that, in the event of a yes vote, Alex Salmond and his ministers would have the UK Government over a barrel when it came to post-independence negotiations between the two governments – the suggestion being that the First Minister could set the highest possible price for delaying the removal of Trident from Scotland.
Last week, Mr Salmond made clear his bargaining position when he declared: "The nuclear weapons concerned are not Scotland's nuclear weapons. If they are regarded as an asset, which I would find difficult to regard them as, then I am quite certain we can trade that asset for something more useful."
During the same June session of the Scottish Affairs Committee hearing, MPs were told by Mr Harvey that the costs of relocating Trident and replicating the complex safety infrastructure south of the Border would be "gargantuan".
He explained: "The costs would be absolutely immense. I would have thought relocation would be just about the least favoured option that it would be possible to conjecture. In the context of that pan-governmental negotiation - if a future independent Scottish Government were to insist upon the nuclear deterrent being relocated out of Faslane, the impact of that on that pan-governmental discussion would be very substantial indeed."