At a Sunday lunch in the 'burbs of north London, the kids run amok around a play fort in the garden that resembles a pocket Alamo; meanwhile, us grown-ups dissect chicken, then use our teeth to suture it to our stomach linings. In the febrile atmosphere of the power vacuum enveloping us - the infinitesimal gap between Gordon and Dave - all seems at once momentous and trivial, as if every question one asks were a request that Bertrand Russell pass the salt. The subject of Britain's Trident nuclear deterrent comes up and our hostess - who, while by no means stupid, has fewer political bones in her body than the chicken - ventures: "But if we were to get rid of it, what if Iran gets the bomb?"

Mrs S patiently explains that, were this eventuality to arise, it might be reasonably accorded Israel's responsibility - as it is their avowed desire - to unleash mega-death on the bearded fanatics of Qom (and a few million innocent bystanders). But I'm gone already, dived deep under the incorruptible Atlantic, down into the depths, where the Vanguard-class ballistic missile submarine describes its quadrangular course across the ocean floor. I consider the crew, who have no contact with the outside world for three months at a time; I meditate upon the captain of this supercharged giant black dildo who, acting on the orders of Gordon - or David - would unleash missiles armed with multiple nuclear payloads.

For that's the sop to the submariners' consciences: they may push the button, but they will never know point of impact, except in the eventuality that Gordon - or David - is himself carbonised, in which case the captain must read the personal letter from the prime minister of the day, which reposes in the safe, and which will authorise him to fire at his own will. What will the captain do, I ponder, if David succeeds to the premiership? Will he leave off his boxing of the seas to return to HM Naval Base Clyde, at Faslane and pick up a new letter, or is he instructed to take it on trust?

Mad to work here

Either way, this rusted link in the chain of command encapsulates all the corrosive psychosis of that most insane of collective delusions, the national security doctrine known as "Mutually Assured Destruction", or by its entirely apt acronym, Mad. While it may be true that in the cold-war stand-off between the US and the USSR, Mad prevented the annihilation of both empires (and, following the diversification and ramping up of weapon systems, the collateral destruction of the entire world) by making a nuclear first strike suicidal, there's no reason whatsoever for Britain being Mad, any more than there is for Sweden, or Senegal.

Indeed, it's fair to say that by taking Polaris from the States, and thence Trident (both systems having been developed in the US and the technology leased to us), successive British governments have also taken a job lot of mass paranoia. After all, while Gordon or David may delude himself that he's entirely independent when it comes to vaporising Moscow - or Tehran - the fact of the matter is that no such action could ever be taken without Barack's say-so.

Psyched up

I often observe the effects this extreme double-bind has on the British national psyche. I see it in the vain posturing of our politicians on the international stage; I see it in the state-sanctioned death cult of our armed forces; and I see it most poignantly in comfortable suburban homes where, when replete with Sunday lunch, someone idly considers the necessity of wiping millions of people off the face of the earth as a reasonable exercise of self-defence.

But that was then - and this is now. With the Bullingdon boy in No 10, and the camp Yorkshire slaphead in the Foreign Office, I quite appreciate the pressing need to extract the country from the maw of bankruptcy. Still, there is such a thing as killing two birds with a single stony inaction: scrapping Trident would save a shed-load of money, while also puncturing once and for all the fantasy that Britain remains a world power.

It would be the political equivalent of the entire country downing a bracing draft of Largactil, and starting to recover from the post-traumatic stress disorder of the 20th century. As any good therapist could tell Dave, confronting reality is the first step towards positive mental health - but then positive mental health isn't why Dave went into politics, is it?