The Bourne Ultimatum (12A) ****

The message being, never mind the slicksters who had gone before and meet the 007 who is not afraid to get his hands dirty.

In British director Paul Greengrass's film, it is the turn of renegade CIA agent Jason Bourne (Matt Damon) to get busy amid the ceramic tiles - not once, but twice. It's as if Greengrass and Damon were taunting the Bond gang, adopting an "anything they could do, we can do better" attitude. Newsflash: they have.

What Bond did to his assailant, The Bourne Ultimatum does to the wearied conventions of the action movie. Never mind a 12A rating from the BBFC - such is the straight-to-the-veins adrenalin rush it delivers, Greengrass's picture ought to come with a health warning.

In this, the third in the series, Bourne continues to be a soul in torment, searching for answers about his past. According to the evidence, he's an assassin who has somehow slipped the net. He, however, can't remember a thing - not even whether Jason Bourne is his real name. The only certainty is that his enemies, and his former employers, want to terminate his contract by terminating him.

The role of Bourne is so tailor-made for Damon it surely came with a Savile Row label attached. As an actor, he has a tendency to be too buttoned down for his own good.

In his last screen outing, The Good Shepherd, he was low-key to the point of inducing sleepiness in audiences. But this pared-down style suits Bourne, a half-dead man walking. When the occasion demands, Damon allows his emotions to seep through, skilfully showing Bourne to be a mix of reluctant killer and little boy lost.

It's hard to think of another actor with the intelligence and sensitivity to strike such a balance.

This time round, Bourne is not the only one on a quest for answers. London-based reporter Simon Ross (Paddy Considine) has been successful enough in his digging to attract the attentions of the CIA, represented by Bourne regular Pamela Landy (the divine Joan Allen), and the National Security Agency, the new kids on the war-on-terror block, led by creepy Noah Vosen (David Strathairn).

When Bourne reaches out to the reporter, the spooks go after both of them. This occasions the first of the film's many breathtaking pursuits as Bourne tries to keep the panicking reporter safe while saving his own skin. (At this point, professional solidarity forces me to object to any journalist being portrayed as a snivelling coward when the heat is on. Have these scriptwriters never seen a hack defending an expenses claim?)

During the chase sequences, everything seems to happen at triple speed. It's a mad, mad whirl of multiple protagonists and hand-held cameras all dancing to the beat set by John Powell's pumping score.

Bourne has all the moves, all of them gobsmacking. It's a good half hour before Greengrass lets the audience draw breath.

As he showed in the previous Bourne and the Oscar-nominated United 93, this is a director with a genius for setting pace. He's not afraid to plunge from one extreme to the other, from cacophony to calm, because he knows that the quiet moments can hold as much tension as the noisiest.

At the same time as the viewer's brain is telling them to relax and savour the down time, the body says don't bother because at any moment the pandemonium will start again. It's the fight/flight response every action movie director dreams of provoking in an audience. Greengrass has it nailed.

The action zips through the zip codes - London, New York, Turin, Madrid - before reaching Tangier for a spectacular, across-the-rooftops-and-through-buildings chase that culminates in one of the aforementioned bathrooms. The stunts are so audacious, the only rational response is to laugh at the sheer bally cheek of it all.

Since they're operating in the realm of fiction, Greengrass and his scriptwriters can afford to go to town. Even though the spooks stumble now and then, the film can't quite resist playing up to the familiar myth of the security services as all powerful and ruthlessly efficient.

Bourne himself is nothing less than a superman. It's all fun, fine and dandy, until you remember that the likes of London and New York were home to real-life carnage and mayhem the secret services didn't see coming.

Another minor cliche that somehow managed to slip through the vetting process is a scene where a female character in need of a new identity takes to the bathroom - yes, that room again - with scissors and hair dye. Despite no formal training, like many before her she somehow emerges with a "do" that wouldn't disgrace a senior stylist at Sassoon's.

Having drawn his portrait of the new world security order, Greengrass leaves us in no doubt who the good guys are by making the character of Noah Vosen so loathsome. "We're the sharp end of the stick now," he tells Landy, requesting another assassination as casually as he orders lunch.

Vosen's fraught relationship with Landy is well handled, but it's the tussle between her and Bourne which really rattles the windows. She wants the boy home, and the agency's "dirty little secret" to be kept quiet, but she wants everything done by the book. To even hint at whether she gets her wish would be to spoil an ending so brilliantly executed it merits compulsory study in every film school.

Greengrass has shown there's no such thing as the curse of the threequel if enough wit, talent and inventiveness is deployed. In the summer battle of the blockbusters, he who dared has won.