Last month Ben Elton said something which, though not funny, was still unexpected: “There’s no doubt about it, the BBC will let vicar gags pass but they would not let imam gags pass. They might pretend that it’s, you know, something to do with their moral sensibilities, but it isn’t. It’s because they’re scared.”

If so, the BBC would hardly be the first to quiver. The transvestite potter Grayson Perry admitted recently that he wouldn’t attack ­Islam in his art because “I don’t want my throat cut”.

But while Elton’s and Perry’s interjections are new, what they have observed is not. The knowledge that writers, film-makers, artists and cartoonists have tiptoed around even mentioning Islam is hardly novel. Since the 1989 fatwa on Salman Rushdie, and even more since the murder of Theo van Gogh, it’s a rare public figure who doesn’t save their political “bravery” for attacking George Bush, the Iraq war or perhaps the “Zionist entity”.

Hollywood directors continue to churn out dramas with Cold War enemies. The British television spy drama Spooks avoids the one terrorist threat that the public is actually thinking about. Public intellectuals like Richard Dawkins hold back on Allah in a way they refuse to do with other people’s deities.