Prosecutions for the possession of the filthiest pornography confirm foreigners' suspicions that the British care more for animals than people. Between 2008 and 2011, the English and Welsh authorities charged 1,922 men for having images of bestiality about their person. By contrast, they brought only 310 prosecutions for possession of pornography that simulated serious or life-threatening injury on members of the human species. For necrophilia, they managed four. And there have been no prosecutions at all of those who downloaded images of rape.

The United Kingdom's Criminal Justice and Immigration Act of 2008 defines "extreme pornography." It holds that rape is not extreme enough to be worthy of the law's notice. The authorities punish those who find pleasure in the abuse of sheep but not in the abuse of women. Censorship rarely rests on coherent principles.

Perhaps because of an administrative error, however, the British government's refusal to criminalize simulations of rape featuring consenting adult actors has a logic behind it. Liberals stick, or ought to stick, to variations on philosopher John Stuart Mill's "harm principle": adults can do, read and watch what they want as long as they do not directly harm others. They are free to express radical views the mainstream deplores, unless they urge readers to murder a banker or plant a bomb. They are free to be a racist or a homophobe. But they are not free to bawl racist or homophobic slogans to mobs by a mosque or gay bar.