Harare — Jason Bourne (Matt Damon) has it explained to him, while we the audience listen in, how his loss of memory made it impossible for him to know his origins. Since this is the final instalment of the series of three films, each based on the three award-winning novels, we can applaud the summing-up. Nothing, we learn, is as it appears.

"Jason Bourne" is not even his name. Apparently there is deeply embedded in the American security-anti-terrorist mindset the need for an organisation so secretive that none of its operatives is permitted to know the real name of his colleagues.

For reasons never explained, "David Webb" approached this highly secretive government body about 10 years before the onset of the current instalment and offered his services as an assassin. Dr Hirsch, played by Albert Finney, the 71-year old English-born actor, whose second recent film this is, after an absence of more than 30 years, has recruited the naïve and innocent David Webb and turned him into a psychopathic killer named Jason Bourne. If you are dissatisfied with his untangling of the plot, there is nothing you can do about it; this film is the last of the lot. Little of this may appeal to or captivate the typical Harare audience, but The Bourne Ultimatum is a masterful, high-budget, superbly photographed example of today's level of high-end filmmaking.

What will keep its audience on the edge of their seats is the several fast action chases through the thronged streets, not only of New York, but Paris, London and Tangier, Morocco. If the American CIA's bureaus for protection against international terrorism are as porous and inept as depicted here heaven help them if their enemies get serious again. Keep an eye on the actor David Strathairn, recently seen as Edward R. Murrow in the film Good Night and Good Luck. Always considered highly competent, he has only now, after dozens of grade B films and at the age of 58, been given a real opportunity to show his talent.

Here, his role is as the completely misguided head of the security forces who refuses to heed the advice of his second-in-command (a woman) Joan Allen plays this role in her usual tight-lipped, long-suffering persona.

The Bourne Ultimatum

Cast: Matt Damon, Julia Stiles, David Strathairn, Joan Allen, Albert Finney.

Director: Paul Greengrass.