This full-blooded gore-fest is not quite the sort of thing you'd expect from a director whose previous outings include More Great Vegetarian Dishes.

James Wan put such nourishing TV offerings behind him to write and direct this fiendishly contrived horror yarn, with pretensions to a moral fable.

Two men wake up chained to the wall of a subterranean bathroom to be told that one must kill the other in order to survive within eight hours.

Their judge and jury is the mysterious Jigsaw... but he's not the sort of chap to be found assembling giant pictures of Constable's Haywain.

A calculating sadist who has so far managed to evade the police, he uses his time dreaming up ever more elaborate methods for his victims to die.

Occasionally he overdoes it - check out the poor sap covered in flammable gel who has to blunder round a dark room barefoot on broken glass while searching for the combination to a safe that holds the key. While holding a candle.

This time hospital surgeon, Lawrence (Elwes), and his cellmate, Adam (Leigh Whannel), learn via micro cassette messages and hidden notes what fate has in store.

They're supplied with blunt hacksaws, one bullet and a gun while Lawrence is also allowed the luxury of a mobile phone so he can hear his kidnapped wife and kid scream.

It seems they've incurred the displeasure of Jigsaw by the morally questionable way they lead their lives... but they don't actually seem that bad.

We also learn that Jigsaw was cornered by Detective Tapp (Glover)... but managed to get away after an ingenious arrangement of shotguns did for Tapp's partner.

Retired from the force, can Tapp turn it on and reach Jigsaw before Lawrence and Adam are limbering up for a bloody fight to the death?

The sort of movie that likes to revel in its own notoriety, this will impress fans of Cube/Se7en-style chillers, even if it is riddled with inconsistencies.

A bit too elaborate for its own good and taking one twist too far, it is redeemed by gallows humour and Wan's indisputable skill at cranking up the tension.

To those who like their horror visceral and twisted... you're saw-ted.

Tim Evans