WHY on earth does Britain need to maintain weapons of mass destruction?

At a time when Nato's secretary-general Jens Stoltenberg is urging members to spend more on defence after warning that 2014 had been a "black year" for European security it's a question worth asking. Next year a decision will be taken about replacing Britain's soon-to-be-obsolete Trident weapons system and the government of the day will be doing its best to push through a budget which could rise to £100bn over the next two decades. Astonishingly, this represents one-third of all funds available for defence procurement, a staggering sum. It doesn't matter who wins the election either as all three UK parties support the continuation of an independent nuclear deterrent.

But why wait until after the election because this is a basic matter which affects us all now and is crying out to be debated. Does this country require an independent deterrent which is capable of killing hundreds of thousands of civilians and destroying the cities they inhabit? Similar-sized nation-states such as Germany, Italy and Spain seem to manage without them and in any case, have these weapons been of any use in recent wars in Iraq and Afghanistan? Can we deploy them against the Islamic State to discourage the beheadings and to stem the steady tide of fundamentalism? It is unlikely that the ghastly fighters of Boko Haram quail in their boots in west Africa because France, a previous colonial power, possesses nuclear warheads.

For anyone with an iota of humanity or reason, the short answer to the wisdom of possessing WMDs has to be a resounding "no". Consider the facts. Trident's replacement will be brutally expensive, it will soak up funds the country does not have and, more than anything else, it is totally unnecessary. It's a Cold War weapon that has long passed its sell-by date; the world has moved on since the bad old days when politicians on both sides of the Iron Curtain were taught to refuse to blink and senior commanders ramped up their demands for bigger and better toys even if they had to forge the evidence to get them.

Apologists for Armageddon claim that the Cold War remained cold because both sides had the means to unleash destruction on whichever country threatened them. This is an oft-quoted argument but it flies in the face of facts. In 1982, President Galtieri of Argentina was not deterred from invading the Falklands and I cannot remember President Leonid Brezhnev worrying too long about the Prague Spring of 1968 before deploying 200,000 Warsaw Pact troops and 2,000 tanks to invade Czechoslovakia. In the post-Cold War world of terrorists lightly armed with AK-47 assault rifles and rocket-propelled grenades, the argument becomes even more difficult to sustain.

Also in the realms of make-believe is the tenuous notion of "prestige". To a large extent, Britain owes its position as a permanent member of the UN Security Council to its possession of nuclear weapons and once upon a time that might have been to our benefit. It was supposed to bolster the special relationship with Washington but look where that has taken us in the unwinnable wars in Iraq and Afghanistan. In any case while our warheads might be our own, the Trident D-5 Missiles are American-built and while the coding is a matter of national security there is ample evidence to suggest that Washington retains the capacity to over-ride the firing of UK missiles, accidental or otherwise. The reality is that Trident is no more independent than Scotland would be in the event of another No vote.

Besides, there are more sensible alternatives for a country which has no further need to try to influence world affairs by maintaining a fleet of nuclear-armed submarines to swan around beneath the world's oceans. If we require nuclear warheads in time of crisis, apparently they can be flown in by cruise missile or even in extremis by drone - the weapon of the future - but this does not send a very encouraging message to countries such as Iran, who might entertain similar ambitions.

Speak to any senior military officer these days and the topic rarely strays from defence cuts. More pain to come is the general opinion as they reflect on a future dominated by smaller numbers, reduced budgets, less capability and overall decline. Amidst the continuing uncertainty, the dreaded "T" word is usually avoided, not because it's a non-issue but because it is largely irrelevant to their needs. It's one for the politicians and the lobbyists to decide. Otherwise they want to continue doing what they do best: confronting the country's real enemies in hot, sweaty and dangerous places where the enemy does not cower in their tents because they are terrified that grotesquely expensive nuclear weapons might one day fall on their heads.