TELEVISION / Paranoid? Who are you calling paranoid?

I'M NOT quite sure where to begin with Chris Petit's film for Bookmark (BBC2). Nor was he by the look of it, quite apart from not being sure what to put in the middle or how to end the damn thing. At one point Petit's despairing voice could be heard on the soundtrack saying, 'I don't think I can finish this . . .' He was talking about completion but for some reason the phrase brought to mind a child in front of a cold plate of liver and broad beans. I didn't think I could finish it either but I'm paid to eat up, so I soldiered on, choking down its grimly synthetic mysteries and laborious, self-referential tricks.

The subject matter, ostensibly, was the thriller and particularly that realm of the genre that deals in millenarian doom and conspiracy. The conceit was that the impulses which fuel such books, the uncertainty and paranoia, begin to leak over into the making of the film. This was the cue for surveillance imagery of Petit meeting his contributors, for dodgy camcorder footage of him talking to his commissioning editor about the project, for interminable dramatised sequences in which the director became involved in some inexplicable conspiracy.

Some of the ideas were good - the furtive, conspiratorial look to some of the shots, snatched through car windows or filmed distantly through plate glass, provided a nicely distressed frame for the interviews with writers like Michael Dibdin and Daniel Easterman. The locations for the interviews were just right too - a lobby like a Richard Long painting, airbrushed and spookily neutral, and anonymous hotel bedrooms. But it was a film suffocated by ideas, reminding you how easily the ambition to be different can muscle out the ambition to communicate. At one point Petit's young son picked up the camera for a couple of wobbly shots (including a long image of the director's shaving water going down the plughole), sequences which may have been a sly response to the traditional dismissal of experimental work ('My seven-year-old could do better than that') but were more likely just another undisciplined impulse. I was a bit paranoid myself by the end, speculating about a secretive group of old chums at the BBC, all letting each other get away with murder, but on reflection I think it was probably cock-up rather than conspiracy.

'Thriller' made an interesting companion piece to last night's Walk on the Wild Side (C4) about computer hackers. The series is a pretty straightforward shot at the youth market, but there were some startling stylistic echoes of Petit's film. Both programmes cropped faces into fragments, both made a point of conspicuous censorship of some contributions, both had fun with computer imagery. In Petit's case, these were affectations - when Francis Wheen was talking about real conspiracy theories, there was no particular legal reason for bleeping the names he uttered (which were obvious anyway) - it was a fake amplification of mystery.

In the case of 'Hackers', the circumspection was the real thing. The hackers who half-appeared couldn't show their faces because they are engaged in illegal activities and even the non-judgemental approach of this series (it's essentially careers advice for juvenile delinquents) faltered at the prospect of broadcasting a detailed description of how easy it is to commit credit-card fraud. 'I had too much to drink one night and thought I'd have a chat with the Queen,' said one, claiming that he'd discovered the Buckingham Palace direct lines.

Another showed how easy it was to rig up free phone-calls anywhere in the world. I could get all moralistic about this sort of activity, I suppose, but I'm frightened that if I do, someone will access my bank account and set up a huge monthly standing order to the Ulan Bator Zoo. Either that or give me a criminal record for parrot smuggling. So I'll just say that they all appeared to be young men of exceptional application and energy which might be better applied in charitable work. Call me paranoid if you like but you have to be careful.