TELEVISION / A spirit of inquiry

NIGEL Williams' novel Witchcraft opens with a hilarious scene in which a scriptwriter attempts to circumvent the obstructive bureaucracy which stands in the way of a British Library reading ticket. Nigel Williams' film Witchcraft (BBC 2) opens with sombre music and an image of a gruesome-looking scarecrow. The choice of first notes turns out to be instructive; where the book achieved its effect by an unsettling modulation away from exasperated comedy, the film goes all out for gothic melodrama.

The essential story remains the same though - that of a writer who is gradually possessed by his subject and finds that what appears to have been safely consigned to the dustbin of history still has a disturbing vivacity. Jamie Matheson has written a film about Ezekiel Oliphant, a 17th- century witchfinder who hanged his wife and his mistress. To further his research Matheson looks up his old history tutor (Alan Howard) and discovers that Ezekiel's story has some odd parallels with the present. Casual talk about wanting to 'dig him up' and 'flesh him out' may cost lives.

Where the novel flickered between the past and the present like a faulty television, leaving the reader to decide just where imagination stopped and the supernatural started, the film is more blunt, pulling back from historical scenes to show the straggling camp-followers of a contemporary film-shoot. The film-within-a-film is surprisingly good; shot through a smoky orange haze and packed with extras, it never looks as if it was shot with the tea-money once the real stuff was finished. Elsewhere, though, it gives the story some problems, forcing Williams to substitute slightly unconvincing debates among the cast and crew for what were neurotic introspections in the novel.

To most people watching, this won't matter a damn but even on its own terms the film doesn't quite seem to have worked out the problem of how a genre idiom can be used for serious purposes. Almost every accessory from the Catalogue of Gothic Effects turns up somewhere or other - long stares from leaded windows, sudden electricity failures, rattling casements, hooting owls, peals of thunder, clocks striking midnight, man-going-into-the-cellar-for-no- good-reason. This is all good fun but tends to undermine the larger ambitions of the piece, its thrust at the nature of evil and the recurrence of history.

As Alan Oakfield, the tutor, and as the spirit of Ezekiel himself, Alan Howard gives a performance of similar ambiguity, at one point rolling his eyes like the last home in the 3.30 at Chepstow, and at the next introducing a chilling note of genuine malignity. But how are you to take scenes like his vituperative dinner with his boss, in which they trade funny but barely credible insults? If their mutual loathing is this intense why on earth did one send the invitation and the other one accept? Perhaps it's only appropriate for a spooky thriller but Witchcraft creaks a bit here and there.