LAST Thursday night I nearly choked on my glass of Blue Nun (favourite tipple of BBC's This Week) when Michael Portillo, the former Tory defence secretary, told the presenter Andrew Neil, not only that he thought Trident was a nuclear anachronism, but that more than half of the army chiefs of staff agreed with him that it should not be renewed.

It wasn't the only nuclear shock. Speaking on the LBC radio station, the Deputy Prime Minister, Nick Clegg compared Trident to pre-World War One Dreadnought battleships, and questioned the wisdom of a weapons system designed to obliterate Russia when the threat from the former Soviet Union had evaporated. Never before has an acting Deputy PM posed the question in this way.

The Liberal Democrat Treasury spokesman, Danny Alexander, then came up with a plan to partially decommission Trident by scrapping one of the four Vanguard boats and ending the practice of having at least one submarine armed and on active patrol 24/7. He was sat upon very firmly by the Tory Defence Secretary, Philip Hammond, but clearly, something is in the air.

What has this got to do with the Scottish independence referendum? Quite a lot, actually, because the mere possibility that Scotland might go it alone and call for removal of weapons of mass destruction from the Clyde, seems to have prompted a rethink of the system. For the first time in my lifetime, a significant proportion of the UK political and military establishment is asking serious questions about not only where to put Trident, but whether we need it at all.

Now, as our lead story pointed out last week, removing Trident from the Clyde would only cost around £150 million. The problem is relocating it to England. There's nowhere for it to go, even if the Government could afford £20 billion on building a complex like HM Naval Base Clyde. Trident submarines could theoretically be stationed at Devonport or Falmouth, but no-one wants nuclear submarines in the English Channel. Or anywhere near contested parliamentary seats.

The truth about Trident was that it had to be located away from "centres of population". Scotland not only had deep water, it was far from the Home Counties. The fact the Clyde is a few miles away from Scotland's main centre of population, Glasgow, didn't figure back then.

But now, because of the referendum, the MoD has had to look at contingency plans should Scotland vote Yes. Some of the ideas were frankly barking, like designating the Clyde Naval Base as "sovereign territory" of the UK, a nuclear fortress in a hostile land. Then there was the idea of getting an independent Scotland to pay to relocate Trident. You and whose army, said the SNP.

Hardly had they been floated than these Trident solutions sank without trace. Number 10 made clear that it has no plans for a nuclear Guantanamo Bay on the Clyde. The idea of charging Scotland £20bn to remove weapons of mass destruction – almost certainly illegal under international law – has also been back-pedalled. The official MoD line now is that it is not thinking the unthinkable any more because it is confident that there will be a No vote. Well, maybe.

But the questions won't go away. The Soviet Union and the Warsaw Pact military alliance collapsed more than 20 years ago. Yet, for three months of the year, a British submarine carrying enough nuclear warheads to destroy 100 Hiroshimas cruises the Atlantic, in radio silence, ready to respond to a pre-emptive strike from an "evil empire" that is no more. This is not rational. Trident 11 D5 missiles are designed to travel 7000 miles through space at a speed of 13,000mph. What use are they against a terrorist with a suitcase bomb, which is a real security risk?

Of course, Trident is not just for defence. It is an integral part of British national prestige, and supposedly gives the UK the right to sit in the Security Council of the UN. Though what actual benefit that confers on the British citizen is not clear. The days when you measured a country's international standing by the size of its weaponry is past. Germany and Japan don't need such virility symbols.

But what if the risk of nuclear threat in future is from North Korea, Iran? It is, as Nick Clegg said, absurd to retain weapons systems for hypotheticals. "We don't have standing armies on the white cliffs of Dover just in case someone decides to invade Britain across the Channel."

Of course, not only have the Conservatives rejected Danny Alexander's "three-boat" solution. Anti-nuclear campaigners say it is tokenism, and it is. Britain would still be a nuclear state, albeit one that no longer has a first strike capability. But I think the proposal could, just possibly, mark the beginning of the end for Trident.

There is a parallel with the decommissioning of IRA weapons, which took a long time and started with a policy of no first use. Many denied the sincerity of the IRA high command. But decommissioning led eventually to the arsenals being allowed to rust in peace, even though the IRA never explicitly abandoned its military capability.

So, why not nuclear decommissioning? Britain could belatedly fulfil its obligations under the Nuclear Non Proliferation Treaty by ending "continuous at sea defence". Then, instead of renewing the system after 2020, the Government could extend the life of the existing boats, as the Americans have done, from 25 years to 35 or 40. Britain would still have a "nuclear deterrent", only it would not be fully operational and would gradually become obsolete. The Government would save about £4bn a year, without appearing "weak".

For Scotland – as this column has long argued – decommissioning could be key to resolving the post-independence problem. The Astute-class and Vanguard submarines could remain in the Clyde as a conventional force, with the nuclear warheads retained in the British Weapons Establishment at Aldermasten in Berkshire.

Yes, it would be a fudge. An independent Scotland would still be conniving in the maintenance of a nuclear weapons system, even if those weapons were no longer on Scottish soil. However, fudge is how politics works. When the time came to renew the submarines in 2030, public opinion would have come to accept the idea of Britain no longer willy-waving in the negotiating chambers of the world. Even today, 60% of us either want Britain's nuclear arsenal scrapped or reduced.

Britain could seize the moral high ground as the first Western country to honour the spirit, and not just the letter, of the Non Proliferation Treaty, which obliges all signatories to remove weapons of mass destruction from the planet. If we want to stop countries like Iran acquiring a nuclear bomb, someone has to set an example. Even the defence chiefs would be happy because they would have more money to equip the British army.

And all because of Scotland's referendum.