Think of the modern political thriller and the image that comes to mind is likely to be Matt Damon as Jason Bourne, slaloming through Tangiers on a Honda Cota 4RT. Then compare Bourne with the writer at the centre of Roman Polanski's The Ghost. In one scene, this nameless hack sets off on a fact-finding mission that will place him in grave danger. He mounts a bicycle, wobbles a bit, pedals uncertainly for a few seconds, then sinks into the gravel driveway. Pathetic. In the time it takes him to cycle a metre or two, Bourne would have defused a bomb with his teeth, hacked into the Pentagon computers using only a paper clip, and called Gardeners' Question Time to outwit Bob Flowerdew with a poser about bindweed.
The chasm between these two makes of political thriller is vast, but the surprise is that the superficially slower model represented by The Ghost proves as sturdy as ever. Polanski and his co-writer Robert Harris have whipped up a pleasurably preposterous yarn - faithfully adapted from Harris's novel - which feels both old-fashioned and timeless. Like the writer on that pushbike, everything moves at a measured pace. If a character is going on a car journey, you can be sure we'll see the door close, the seat belt being fastened, the vehicle pulling away - only the search for a radio station not playing Michael Bublé is omitted. But the film never drags. Polanski's fetishistic attention to detail transforms innocent objects into potential clues. His deadpan sensibility introduces the possibility that anything, however horrific, can be fascinating or perversely absurd.
One of his smartest tricks is to liberate the narrative from its real-life resonances. When the novel was published in 2007, it acquired a reputation as a roman à clef on account of the character of Adam Lang, a former British prime minister accused of war crimes after handing al-Qaeda suspects to the CIA for torture. Should that not ring any bells, he also has a tendency to call people "man".
On screen, it transpires that there's nothing disingenuous about the standard "Any resemblance to persons living or dead . . ." disclaimer, give or take the odd Elvis sneer from Olivia Williams, who plays Lang's wife, Ruth. A former foreign secretary sceptical about the invasion of Iraq is played by Robert Pugh, an actor who won't find work as a Robin Cook-o-gram, should demand for such a thing ever arise.
As Lang, Pierce Brosnan has a hounded, ungainly quality that makes him seem rather pitiful; he paces around the glass-and-steel seafront home of his US publisher like a raggedy lion at a downmarket zoo. His ghost-writer (Ewan McGregor) is distracted by thoughts of his own predecessor on the project, who left behind a manuscript before being found washed up on a beach in a tableau that in no way recalled From Here to Eternity.
Having disqualified himself from making a crypto-biopic (My Blair Lady? Blairy Movie?), Polanski has crafted a classical espionage film that in its generalities ends up commenting on the depreciation not just of New Labour, but of any ideology that betrays itself. Watch it alongside Green Zone, the recent Iraq-set action thriller from the Bourne team, and the supposedly edgier film seems dated in its fidelity to yesterday's news. The effect of harnessing Polanski's patient, old-school suspense to a plot invoking Iraq and the "war on terror" is to absorb our present-day concerns into thriller conventions, as though arguing that these crises are nothing new - they've always been part of our narratives and our consciences.
During the opening scenes of The Ghost, the "Europudding" bell may ring loudly in the viewer's head as Berlin, complete with double-decker bus, stands in for London, and the German island of Sylt impersonates Martha's Vineyard. (There's a snatch of Euro-movie dialogue when Lang mentions "the Times of London", a phrase that no one without a monocle has used in 50 years.) But even this contributes to a reassuring sense of banality which ill prepares us for the approaching abrasiveness. To say more would spoil the touch of genius that raises The Ghost from good to great. Let's save that for a few years down the line, when we'll celebrate the uncompromising pay-off as freely as we now applaud the acid-in-the-face that passes for an ending in Chinatown.