I just cannot get enough of the Scottish referendum debate. On every side the unthinkable is thought, the unsayable said. The murky covers are removed from North Sea oil, the single currency, the Barnett formula, welfare dependency, the West Lothian question, revealing swamps of intellectual confusion our rulers would rather keep hidden. None is murkier that the fate of Faslane and its Trident submarine base.

No matter that most defence chiefs have long wished Trident to vanish in a puff of smoke. None has the guts to say so. The Treasury pays up so no one rocks the gilded boat. Faslane and its missiles will cost British taxpayers £100bn over the next 25 years, and for what? Britain could invade a dozen countries and seize their terrorists for less.

Alex Salmond has promised that, if his people vote for independence next month, all nuclear weapons will be off Scottish soil by 2020. The result has been an outbreak of panic among the normally somnolent dogs of war. Where will the submarines and their warheads go if not in Scotland? The wild, unpopulated Scottish lochs are not easy to replicate in England or Wales.

A BBC programme on the topic by Andrew Neil on Tuesday revealed a cast of gloom-laden defence pundits bewailing Britain’s “loss of influence” if Scotland were “lost” and Faslane closed. The UK would be humiliated, downgraded, demoted to the second division. Our seat at the top table would be removed. Hardly anyone mentioned defence, just prestige. The language was that of faded imperialists out of their time. The world in which these people move is not one of soldiers, guns and bombs but of thinktanks, travel grants and seminars. The only power they know is PowerPoint.

A report this week from the Royal United Services Institute (Rusi) is more relaxed. It points out that the ailing nuclear submarine base at Plymouth’s Devonport could do perfectly well as an alternative to Faslane. The removal cost would be a mere £3.5bn. The warheads could be stored in the Fal river fjords off Carrick Roads. If you want to dump nonsense somewhere there is always somewhere to dump it. The chief objection to Plymouth is the near certainty of it playing host to a permanent camp of west country CND. Nor have we yet heard from the Cornish nationalists lurking just across the harbour.

An intriguing insight into the politics of nuclear weapons is Rusi’s tangential dismissal of concerns over an “accidental ignition of one or all of a submarine’s Trident D5 missiles” and the resulting contamination of 260,000 Devonians. The ignition of the warheads would also make a dreadful mess of Truro. Apparently, the defence ministry has the right to “waive safety requirements” where it is “in the interests of urgent national security”. The same would apply to any embarrassing opposition to planning permission from local communities. Security can always be waived in the interest of security.

That is not all. The truth is that when you open this can, any number of worms will wriggle out. The Rusi report raises other nuclear options. It discusses basing Britain’s deterrent where it surely belongs, in the US (birthplace of its missiles). There would be plenty of time to move it back in case of heightened international tension.

The argument against is that the weapons might not be immediately available were Britain to want to use them in defiance of America’s wishes. The concept of an “independent” nuclear weapon deterring any conceivable foe is strange enough without drifting into the realm of fantasy. This beats even the Yes, Minister satire, that Britain’s deterrent was always needed to fend off the dastardly French. Or might the defence boffins really be war-gaming a British attack on the US? If so, why are we told that the Americans retain the secret warhead codes specifically to forestall any independent British use, accidental or otherwise?

The most sensible note in the Rusi report is the final one. It ponders whether the possibility of having to move from Faslane might trigger “a wider national discussion … on whether or not the strategic benefits of retaining nuclear weapons exceeded the costs involved”.

The question is not whether Vladimir Putin, al-Qaida or Boko Haram are remotely likely to launch an attack on the British mainland and yet be susceptible to a Trident deterrent. The question is whether, in the spectrum of existential threats to the British state, nuclear deterrence has any credibility in preference to other forms of defence, especially forms able to make similar claims to such huge resources. Ordinary soldiers come to mind. No sensible defence expert I have ever encountered has any time for Trident. Its sole supporters are those with money in the project.

A more general question follows from this and applies to all multibillion-pound projects whose sanity moves in inverse proportion to their price tag. They include HS2, nuclear power stations, Heathrow runways, aircraft carriers, garden cities and universal credits. As soon as each megaproject is announced in Whitehall, a rabble of salivating bankers and lobbyists (many of them paid parliamentarians) forms a chorus to shout down any sceptic as variously killjoy or unpatriotic. The real victim is always the taxpayer.

John Maynard Keynes advocated boosting public spending by burying pots of gold in the ground and paying the unemployed to dig them up. George Osborne makes Keynes seem stingy and unimaginative. Not long ago, the Treasury was the one government institution prepared to call the bluff of such megaprojects and hold them to account. It showed lobbyists the door. It was the intellectual powerhouse of the public sector.

Not today. Osborne may be ruthless towards current government spending. He can guard a candle-end. But the sight of a truly daft megaproject has him rolling on his back with his feet in the air, cash oozing from every pore. Trident is just such a project.

If the Scottish referendum does indeed force the absurdity of Britain’s nuclear deterrent out into the light of day, it is worth it for that alone. If it were to go further and kill Trident stone dead, it would be thank you, Salmond, thank you, Scotland.