Philip Hensher: Can no one criticise Rowling?

Pratchett, naturally, found it difficult to agree with this strange assertion. Though his ire may well have been raised on behalf of his own successful, witty and inventive Discworld series, he has subsequently mentioned the very distinguished names of Ursula Le Guin, Diana Wynne Jones, Jane Yolen, Peter Dickinson and Alan Garner.

Most enjoyable is his final thrust. Rowling was reported as saying that she hadn't realised at first that she was writing fantasy fiction. Pratchett says that he "would have thought that the wizards, witches, trolls, unicorns, hidden worlds, jumping chocolate frogs, owl mail, magic food, ghosts, broomsticks and spells would have given her a clue".

He's quite right. Fantasy fiction has consistently been, since the war, one of the liveliest and most interesting genres of fiction, and needed no Rowling to revitalise it. Even now, if you wanted an example of its vivid imaginative life, you'd reach for China Miéville before Rowling.

But another aspect of Pratchett's amusing letter emphasised how deeply weird the whole phenomenon is. When I saw the letter, I thought, "Well, thank God Terry Pratchett's said it." But around books that are seriously financially successful, and especially the Harry Potter novels, a ferocious defence mechanism has sprung up. Anyone who expresses reservations about these books will find their good faith questioned. The accusation, particularly directed at anyone who is a practising novelist, is that he is driven by jealousy.

It's a brilliant manoeuvre. If you are prepared to suggest that a novelist can only be jealous or deferential towards another, more financially successful than he is, then no one could ever be permitted to say anything sceptical about Rowling.

That accusation has been directed at some pretty surprising people, whose distinguished careers might not suggest any great need to envy anyone. But I did think, when Pratchett voiced his concerns, that at least no sane person could seriously propose that he was driven by envy. After all, with 40 million books sold, a devoted readership extending from the naïve reader to the most sophisticated littérateur, no one could suppose Pratchett to have any reason to envy any other novelist's financial success.

Of course, I was quite wrong. A couple of days after his original letter, Pratchett had taken the trouble to elucidate his comments and to deny the imputation that - you guessed it - he was motivated by "jealousy" in his comments. The whole thing is absurd. If Terry Pratchett can't say what he thinks without accusations of bad faith, then certainly the ordinarily successful novelist, who expects to make £100,000 or so from a book, can't feel free to say anything at all. The result is that everyone tiptoes around Rowling and her books.

The accusation of envy is absolutely ridiculous, in most cases. No doubt many people covet Rowling's millions, just as they covet Bernie Ecclestone's or the Bank of England's. Envy, however: well, literary envy is a powerful and passionate thing. I felt overpoweringly envious, for instance, when a month or so ago I read Tim Winton's absolutely brilliant new book, The Turning. But it is hard to imagine such a feeling of envy at achievement crossing any adult's mind in regard to Harry Potter and the Half-Blood Prince.

The way Rowling has been allowed to stand alone because of her financial success, so that she may not be considered honestly by her peers, and her particular genre dismissed from view, is not healthy. There is a republic of letters, and any writer can engage with any other writer. However many copies they sell, they are books for children about a school for wizards; nothing special. You know, we're not talking about Bleak House or anything.