Why are we such incorrigible sexual snobs?

I'm only surprised that everyone's surprised. The first rule of the sexual life – take nobody for granted. And if you can't get by without a few working assumptions, always assume that things are never as they seem. Whoever doesn't look as though he does, does. Whoever looks as though she has better things to occupy her mind, hasn't. Not in a month of Sundays could you imagine those two ever having an affair? Axiomatic, in that case, that not a Sunday goes by that doesn't see them locked in each other's arms.

Shame on us. Shame on us for believing that John Major was too grey to know passion, or too principled (double shame for invoking principles) to act on the prompting of its heartbeat. Too grey? Too grey to stray! Too grey to fall! Too grey to submit to the soft, sucking, swamp pull of loving where you shouldn't! Colour prejudice, I call that – thinking sex is only for the florid. And sex prejudice – thinking sex is only for the sexy.

We are incorrigible sexual snobs. Blame the media, if you have a mind to. By bombarding us with images of the young, the healthy, the wealthy and the beautiful, newspapers and television have usurped our democratic sexual rights in their name. Yes, we also read of deviant goings-on between unattractive people with bad skin living in detumescent suburbs, but there the unexpectedness is the story, the photographs grainy and unflattering, stolen glimpses of ugliness to feed a prurience that is always tempered by irony and contempt.

What are the ill-favoured and malformed doing behaving with such impropriety, we ask. Absurd that they should bother; astounding that they were able to raise sufficient interest in one another in the first place. "Yuk," we say if we are under 16. Otherwise, "Pffh!". Sex, real underhand sex, is for models, rock stars and table-tennis players. Sex is where the air-brushed bodies are. Sex is a concomitant of success. Sex is what happens in popular culture, on a wide screen, in Pornocolour, in 360 degrees Salacious Sound.

Blame the media if you like, but the truth is that high art, too, feeds the same sexual snobbery. How dashing he is, Count Vronsky, the officer who steals Anna Karenina away from the poor schmuck of a husband whose ears are suddenly grown too big. Count Vronsky. There is even a vroom in his name. Count Vroom Vroom Vronsky. Whereas Alexey Alexandrovitch Karenin pales and falls away even as we pronounce him.

Tolstoy is not so gross as to detail the relative performance of each man in bed – though there is, for those who like such things, the symbolism of Vronsky breaking the mare's back – but we know what we know: Alexey Alexandrovitch Karenin is to sex what John Major was to British politics. He bleaches out the light; he is ashen in appearance and pedantic in manner; he cracks his fingers when he addresses his wife; professionally, he is little more than a jumped-up civil servant. Which leaves us with no more, sexually, to say. Whereas Count Vroom Vroom Virility Vronsky . . .

Tosh, all of it. Great novel, tosh sexual premise. Let me tell you about women, Vronsky, and men who crack their fingers. Let me tell you about women and apparently cold grey pedants altogether – George Eliot's Casaubon, would-be author of A Key to All Mythologies, John Galsworthy's Soames Forsyte, etiolated rapist of his own reluctant wife, and whoever else you can think of who has a share in the cliché. The truth is that far from fleeing them, women seek them out. The wonderful truth, reader, is that given the choice between a dessicated scholar and a muscled athlete, nine women out of 10 prefer the scholar.

These are my findings, anyway, based – selectively I grant you – on 20 years of teaching, particularly teaching mature students, at universities and polytechnics. Of course, you could argue, mature women who come to study at university are already predisposed to the life of the mind and, therefore, to people who possess minds. But I ask you in return what it is that predisposes them. The tedium of inhabiting a merely physical world, in most instances. Their boredom with handsome, dashing, practical, and no doubt sexually competent husbands. Now, in their middle years, they are sick of all that and would like to pick a different flower from the garden that is experience and also, maybe, while they're at it, from the garden that is man.

The man most beloved of women I have ever encountered measured five feet six inches in built-up heels, wore a buttoned cardigan in all weathers, had skin the colour of kale, a little rosebud mouth, peeled an apple with such scrupulousness before he would eat it that you thought the world would end sooner, and could barely see. But such lectures he gave! Such deviousness of intellect he demonstrated!

It isn't for me, or for any of us, to wonder what precise satisfactions he doled out in the privacy of his book-lined professorial den, but that he syllogised women into ecstasy, that he sophisticated them into and out of love, worded them to places they had never been before, hermeneutic'd them off the planet, was clear from their faces when they emerged.

It's wonderful to behold, a countenance flushed with love, and no less wonderful to behold a countenance enthused with knowledge, but a countenance enthused and flushed with both, ah! there's a sight to make even a cynic fond.

Sex is never where you think it's going to be. Least of all is it where it advertises itself most. I don't know whether film stars and footballer have more or less sex than the rest of us, but where you are obsessing over diet, fretting about form, careful of your image and watchful of your fame, it stands to reason that you are going to be neglectful of something else.

This is the sneaking democracy of sex. It hogs the stage until the lights dim, then it creeps off to the quietest parties.