First Night: 127 Hours, Toronto Film Festival

Uncomfortable viewing, but a compelling piece of work

Danny Boyle follows up his Oscar triumph, Slumdog Millionaire, with yet another winning film that should cement his place as one of the best British directors working today.

The British director mixes humour with delirious invention in his telling of the story of Aron Ralston, the American climber who was forced to amputate his own arm with a blunt knife 127 hours after it had become trapped by a boulder in Utah in 2003.

Any film that relies on one actor to carry the movie demands a lot of its leading man but James Franco applies a youthful exuberance that makes him so watchable it's all viewers could do not to blink. This ought to be his breakthrough role and will be a strong contender for award nominations.

The action starts with Franco as Ralston, a cocky youngster with a taste for adrenalin. In the opening scenes, we see Ralston trying and, crucially, failing, to find his Swiss Army knife before he sets off for the remote Bluejohn Canyon.

Ralston's love of fast living is infectious, as he finds to his benefit when he meets and attracts two lost attractive hikers (Amber Tamblyn and Kate Mara). They're immediately attracted to his spirit of adventure, which permeates the picture.

The first scenes that caused bottoms to wriggle in their seats comes with a close-up that investigates Ralston's arm, which has been pinned to the canyon wall. What emerges is Ralston's composure and inner strength as he lays out his equipment with his good limb and plots his escape.

The camera work by Enrique Chediak and Anthony Dod Mantle is formidable, but the scene everyone is talking about comes when Ralston, desperate and without water, slices slowly through the flesh around his arm, having broken it against the rock under which it is trapped. He uses a blunt knife, which Boyle shows picking at the ligaments that still attach his arm to his body. Computer-generated shots take us under the skin, where we see the blade knocking against the bone as it saws through his muscle and fat. In a film defined by scenes of breathtaking exhilaration, it is the only scene from which viewers might wish to avert their eyes.