As I write this, immediately after Friday lunch (five Marlboro Lights, three double espressos), I have no idea whether BBC2 transmitted my film on surrealism last night in its entirety or – more likely – with the excisions prescribed by the cut-wallahs.

As I write this, immediately after Friday lunch (five Marlboro Lights, three double espressos), I have no idea whether BBC2 transmitted my film on surrealism last night in its entirety or – more likely – with the excisions prescribed by the cut-wallahs.

One cut was of a balaclava-clad and camouflaged disco band singing to the tune of "YMCA": "Declan are you looking for fun?/ I said Conal can you hold a gun?/I said Patrick how would you like a chum/ To help you wound, maim, slay?/ Oh join the INLA/ Come and join the INLA ..." And so on.

The second was of a green and white striped "Doctor" Ian Paisley lauding the Virgin Mary as a midfield dynamo in the proud green and white of Celtic and singing a nostalgic ditty about Rome – "Where the Pope and the cardinals play/Where seldom is heard a Protestant word ..."

Like any other programme-maker, I am inured to internal censorship and to the invisible batallions of Grundys and Bowdlers who would make self-censors of us all. We evidently share different values, but I'm not unsympathetic to the censors' task. There is much television that I would happily censor – because of its witlessness, formulaic torpor and oafish populism, rather than on grounds of taste and the likelihood of causing offence. I am constantly offended by celebrity chefs, celebrity gardeners, celebrity makeover artistes, celebrity real people – by the entire celebrity galère, now you come to mention it.

I was quaintly forbidden five years ago to allude, in a film on the futility of building churches in a secular age, to the Vatican having turned a blind eye to the Nazis' extermination programme, a form of complicity that is a matter of record and hardly contentious. I seem to recall that someone or other believed that Catholics might be offended. That however was a qualitatively different sort of censorship to that exercised on my programme.

These cuts were made "in response" to the events in America. Perhaps that should read "in all too predictably panicked response", since prior to those baleful acts of mass murder it was perfectly OK to show singing terrorists and a papist Paisley. And now it's not. There is a troubling form of relativism at large here. The link between a couple of choreographed gags and what has happened in the world these past two and a half weeks is tenuous and slight. But then reason has gone to sleep when it comes to such matters, or at least it has been anaesthetised. Its fragility has not been so graphically exposed since the death of Diana, Princess of Wales, and the histrionic aftermath. Irrational phenomena demand the idiom of surrealism to portray them. Surrealism is, of course, nothing more than the name given to the work of a particular epoch in the history of irreason, in the tradition of representing what isn't rather than what is. That, anyway, is what we have long been taught.

We are so used in Britain to a cultural mainstream that represents itself by essentially naturalistic idioms that surrealism is regarded as a sort of frivolity, as not quite serious, as a series of conventions that have been domesticated for decoration and advertising.

But naturalism and its variants are not up to the job of portraying the world of this century, or indeed of most of the last. There were moments during the destruction of lower Manhattan when it looked as though Max Ernst's terrible prophecies of urban doom had come true. And then one realised that they had come true before in the squalour of the death camps.

Irrational art shows us what is imagined in the gutters of our brain. Surrealism is not just a distraction. It is useful, premonitory. Forget the way that it is traduced as a gamut of cosmetic tics. Tate Modern's show is horribly timely. There are works here which – if we can persuade ourselves to see them anew – shine some black light into the ugliest parts of the human psyche. It surely becomes broadcasters, too, to face up to the brutality of the world rather than to engage the ploy of sweeping it under the carpet.

How long are we going to be nannied, how long are we going to be treated as children? Moral confusion is bolstered by panic about "sensitivities"? Grown ups: just say "No".