If a prisoner walks into my consulting room in the prison with a stick, he’s a sex offender; if he has gold front teeth, he’s a drug dealer; and if he’s reading Wittgenstein, he’s in for fraud: for it is virtually a law of our penal establishments that fraud and philosophy are what literary theorists like to call metonymic.

When you work in a prison as I do, white-collar criminals come as something of a light relief. At last someone with whom you can have a disinterested, abstract intellectual conversation! No more talk about alcoholic mothers, brutal stepfathers, and terrible childhoods as the fons et origo of car theft: it’s straight to the meaning of life, the social contract and the metaphysical foundation of morality (they always say that there isn’t any). It’s almost like being a student again, up till three in the morning, trying to work out what no man has ever worked out before.

The fact is that people who commit fraud, at least on a large scale, have lively, intelligent minds. I usually end up admiring them, despite myself. My last encounter was with a man who defrauded the government of $38,000,000 of value added tax. I am afraid that I laughed. After all, he had merely united customers with cheap goods. Unfortunately for him, he had been lifted from his tropical paradise hideaway by helicopter and then extradited. By the time I met him, though, his sentence was almost over. He had