The Westminster Government has rejected a plea by MPs to draw up contingency plans for Trident nuclear weapons system should Scotland vote for independence.

The House of Commons defence committee warned in September that the possibility of Scottish independence "represents a serious threat to the future operational viability of the UK's nuclear deterrent".

The SNP Government has said it will rid Scotland of nuclear weapons as soon as possible after independence. The UK's nuclear warheads are stored at Coulport on the Clyde and carried by submarines based at nearby Faslane.

"The UK Government must now give urgent consideration to contingency options in the event of a Yes vote," concluded the defence committee, which is composed of a dozen cross-party MPs, not including the SNP.

The UK Government has now firmly rejected that recommendation. "We note the committee's recommendations regarding contingency planning," said the formal response from ministers made available last week. "However, the UK Government's position remains that it is not planning for Scottish independence and cannot pre-negotiate the details of independence ahead of the referendum."

The defence committee had heard evidence from Rear Admiral Martin Alabaster, who was head of operations in Scotland at Faslane from 2008 to 2011. He was asked what impact he thought Scottish independence would have on the UK nuclear weapons programme. He didn't disguise his view that it would be serious, saying: "It would be very difficult - in fact, I would almost use the word inconceivable - to recreate the facilities necessary to mount the strategic deterrent, without the use of Faslane and Coulport, somewhere else in the UK."

Experts have suggested it might be possible to move Trident to the Devonport base in Plymouth. But others argue this isn't feasible.

John Ainslie, co-ordinator of the Scottish CND, said: "Scottish independence would be an opportunity for the UK to scrap Trident because, as the former Faslane commander has admitted, it is almost inconceivable that the base could be rebuilt in England or Wales."