Interesting about those football hooligans arrested in Portugal being described as middle class. There was the son of an Oxford academic who was raised in "a £700,000 cottage", a Birmingham university student, somebody in a Burberry cap, and so on.

But had they really preserved their middle-classness, or had they somehow lapsed? One test might be: would I personally be scared of them if they started acting aggressively around me? Because, although a coward, I am not physically scared of middle-class people, and particularly not of people better-spoken than I am. I simply refuse to be. I used to encounter pupils from one of our major public schools on a regular basis, and they'd walk towards me four-in-a-line on the pavement, but I would not be deflected into the gutter; I would plough on through the middle of the group. I was not going to be intimidated by people who had at any stage called their mother "Mummy".

If I were to be selected at random for a good kicking by a gang from a sink estate - and, given my habit of reading novels or, indeed, writing articles in unsavoury pubs, it's probably only a matter of time - a small part of me would be thinking, even as my nose was smeared across my cheekbones: "Well, it's only fair. They've had no advantages in life, and I've had a few."

It would be an occurrence parallel to the three times when I've been burgled as a householder. On each occasion, I felt the sort of relief I experience on paying a tax bill, a sense of some obligation to society having been met, a penance performed. Being riddled with social guilt, I assume that every burglar is Robin Hood, even if the truth is that, like the character Hector in the new Morrissey single, they steal from "the rich and the poor/and the not-very-rich and the very poor".

Equally, I believe that working-class violence must at some level be justified, whereas violence on the part of people who are well off can carry no moral justification, and the consciousness of the moral affront would give power to my elbow in any ruck that might occur between me and, say, some stroppy merchant banker who insists that it is not by accident that I have knocked over his glass of Pimm's during the performance of a string quartet at Glyndebourne.

When violence goes the wrong way in society, against the grain, it has a particularly disturbing, world-turned-upside-down quality. That is why the film If - with nihilistic Old Etonians shooting at police constables - creates such a frisson. Come to think of it, the star of the film, Malcolm McDowell, symbolises English middle-class violence: he also plays the head Droog in A Clockwork Orange, a devotee equally of Beethoven and "ultra-violence". And it is why football hooligans look more frightening when they're wearing clothes from the smarter high-street stores. Some of them do seem to go for a sinister, moneyed, dapper look, just as the Teds of the 1950s did. In 1954, Evelyn Waugh wrote to Nancy Mitford: "Have you heard about the Edwardians? They are a gang of proletarian louts who dress like Beaton with braided trousers and velvet coats, and murder one another in 'Youth Centres'."

As a writer of crime fiction, I want to think that people capable of violence can be decently educated and, to some extent, sophisticated, because then I can give them witty dialogue (or try to). By way of research for a novel, I once interviewed a criminal barrister about her violent young clients. "They are all from the most depressingly deprived backgrounds, and they are all on crack," she said. "But surely there are a few more intelligent and articulate exceptions?" I asked, with pen poised.

The barrister thought about this for a while. "Nope," she said, eventually.