Against a perfect backdrop of the Victorian Sefton Park Palm House, Will Self turns out to promote Dorian. His reworking of the Picture of Dorian Gray is fresh out in paperback, and so he's traversing the country to bark up a few extra sales with a reading and a question-and-answers session. So, in short, you get Self at his worse and his best in one easy package.

Because, really, he's unconvincing as an author. It's what he does, sure, and he does it with relish and enjoyment, but the voice that comes off the page is sluggish; the dialogue dead and the sweet nuggets of inventiveness and carefully arranged imagery buried way too deep amongst a dust of archaic language (the last person I came across who used the word rodomontade was an elderly English teacher - complete with cravat - who was chiding me for being over-florid) and wooden characterisation. And for a man who claims to be bored by talking about drugs, boy, is there a whole pharmacy to be waded through in his fiction: drug references; drug paraphernalia; drug dealers; drug users; drug speak; drugs as plot device; drugs as metaphor and metaphor as drugs. Worse, the voices Self gives to his characters when reading them aloud robs them of another dimension - and they're not starting out with very many to risk.

Yeah, fiction is what he does, but its not what he does best. Because Self is at his best when he's unscripted. Working off the cuff he's witty, sharp and inspired, and being able to watch his thought process dancing out in front of you is a whole lot more engaging than seeing it when he's had a chance to return and revise the life out of it, and while the audience listens politely through the novel extract, when the Q&A kicks off, they listen attentively. Apart from one chap, who can't even wait for questions to be opened to the floor to leap in - he doesn't appear to have anything much to ask, besides a rather tortuous attempt to extract from Will details of his sexuality. Too tortuous, as it turns out, because by the time he gets to the end of his thought, he loses his nerve and replaces sodomite with writer. When Self gets a chance to get a word in edgeways, he's a hoot - discussing the origins of Cock and Bull, praising the joys of fold-down bikes and the Merseyrail Network (presumably evidence of how heroin can warp your judgement) and enthusing over his last visit to Liverpool, when he was stuck in a flat in a rough area of town and set to produce a short story. (This was an artists-in-residence project and not the work of some literary mafia). He also explained his reasoning behind taking part in Shooting Stars - that he viewed it as a way a self-employed writer could fund a period of paternity leave.

The size of the queue at the bookshop table at the end of the event suggests that his attempts to bark up sales worked like a charm, but you still find yourself wondering: are they buying the book because of the writing, or because of the writer? It's a pity that the Will Self being left behind for posterity isn't a patch on the real thing.