The editor of this magazine wrote me a charming letter in which he said 'I suppose I would assume that you were a high church Tory'. I'm certainly a Tory – which is why I find the present Conservative party so distasteful in so many regards – but my high church leanings are confined to an admiration of the liturgy, a love of church music, and an obsession with the architectural history of the mediaeval parish church. Other than that, I am an atheist, and have been for almost as long as I can remember. Just as it is assumed that all socialists abhor fox-hunting, so it is assumed that all Tories are religious. Certainly, most of my acquaintance are. Tory atheists often fall at the last fence. Enoch Powell once told me that, after two decades of Nietzsche-induced atheism, one of the things that had drawn him back to the Church of England was his feeling that, by not participating in it, he was in some way missing out on some crucial national experience.

I suppose it is how I feel if I miss a day of a Test Match at Lord's. Tories love institutions. They love the idea of the nation. When an institution comes to embody the spiritual aspect of the nation, such as the established church allegedly does, it should be pretty irresistible. Sadly – for I regret not having available to me the consolation of being able to believe – I have always been able to resist it.

As a child I was not force-fed religion. My mother is religious. My father, whose second wife she was, was a generation older than her, and had lost his faith walking past what his diaries called 'the rows of unburied dead, with teams of chaplains reading the burial service over them' on the second day of the Somme. As for my own upbringing, it had been agreed that I would be encouraged to find out for myself about the Christian religion of my forebears and make up my own mind about it. Neither parent ever tried directly to influence me. So, at the age of about four, a very sweet older girl from the village was co-opted to take me to the local Sunday School. I dimly remember - this is over 40 years ago - finding everything that was said to me there about Jesus and the Christian miracles utterly implausible. After about 18 months of this, supplemented by a daily exposure to the 'act of worship' at school, I came home and asked my father whether it was possible that someone could walk on water, or turn water into wine, or heal the sick with a touch. He said he thought it was not. I asked why so many people appeared to think that it was. He said that they had convinced themselves that these things had happened, and that was a matter of their private opinion. I said I didn't feel able to share the opinion. After all these years, nothing has yet happened to make me change my mind.

Indeed, all my subsequent experience has reinforced my original infantile view. I have read Darwin, Frazer, Nietzsche and even Gibbon. I have read Martin Luther - one of the great men of world history - and cannot help but wonder why, having gone halfway to the truth, he did not finish the journey. I have read too much history, and have seen how Christian churches in particular were for centuries a weapon used by repressive states to achieve some measure of social control among superstitious and usually uneducated people. I like the idea of heaven, but find it preposterous. I even like the idea of hell – in my deeply unChristian way I have a mental list of suitable future members – but regret to say that that is undeniably preposterous too. I think almost every day, in some context or other, of the possible existence of God: but I reject the notion as soon as it enters my head.

I can understand why, even 50 years ago, the Church of England was thought to be the Tory party at prayer. I can understand why members of the old establishment thought it necessary not just to worship God, but to be seen to worship God. Tories do, after all, stand for order and continuity, and the Church used to be an excellent accomplice in achieving those aims. But the Church of England is no longer like that; and, in the last 50 years, Toryism has become ideological in a way it has not before. It has acquired a system of beliefs that are non-religious - notably in connection with the liberation theology of free markets and the monetary theory of inflation. That does not explain why Tories feel able to be atheists, but it does help explain why this particular atheist, his instinctive views against religion already formed at an early age, later felt able to become a Tory.

As far as I am concerned, there is a scientific explanation for everything attributed to something called 'God'. If I am wrong, no doubt I shall one day find out swiftly how merciful (or otherwise) He is. I do not doubt that, when my life is ending, I shall regret not having the consolation of the prospect of an afterlife, but I can't do it. It defies all reason. And life, as rationalists know, is in the end all about reason. Perhaps when Disraeli called the Tories 'the stupid party' he had in mind their almost tribal religiosity. I respect those who believe in God just as I respect those who vote Labour: I just do not, cannot, agree with them. I will admire the lines of their beautiful churches, or the austerity of the 39 Articles, or the sonorousness of a requiem mass, and see these things created by believers for the greater glory of God as being a welcome part of our common culture: but beyond their formidable aesthetic they can be nothing to me. I am an atheist because I am a rationalist.