Acting up

The Ghostby Robert Harris 310pp, Hutchinson, £18.99

"Power brings a man many luxuries," wrote Robert Harris in the opening pages of his most recent novel Imperium, "but a clean pair of hands is seldom among them." The first volume of a promised trilogy about the life and times of Marcus Tullius Cicero, Imperium was narrated by Tiro, the slave Cicero kept always at his side with stylus and wax tablet. He made a good viewpoint character, the secretary of the most prolific author and orator of ancient Rome: not so much a fly on the wall as a bug in the architecture: insignificant to everyone, alert to everything.

Harris has interrupted his Roman trilogy to write The Ghost, his first fully contemporary novel. Its titular protagonist enjoys, or endures, a position much like Tiro's: a professional non-entity in momentous times, taking dictation from a powerful patron. Anonymous even to us, he's the ghost writer contracted to supply the "autobiography" of Adam Peter Benet Lang, recently retired prime minister of Great Britain. More accustomed to fabricating the memoirs of addled pop stars and inarticulate footballers, our narrator sees his role, or at least pitches his proposal, as the man to "put some heart" into the leaden first draft left behind by his predecessor, a loyal drudge who died in a drowning accident.

Truth to tell, he's out of step and out of his element, and he knows it. Shackled to a terrifying deadline, confined to Lang's unhappy retreat on a wintry Cape Cod, he faces the unenviable responsibility of turning 600 turgid pages of facts and flannel into what the publisher boasts will be "the first full inside scoop by a leader on the west's war on terror". He's barely unpacked his laptop when the news breaks that Lang is to be investigated by the international criminal court on charges of war crimes, if not crimes against humanity. Four British civilians have been detained on suspicion of terrorist intentions and handed over to the Americans for interrogation, which means torture. Richard Rycart, an estranged former foreign secretary, has a letter signed by Lang that appears to authorise the arrests. Tension and division of all kinds jangle in the corridors of international power, the labyrinth of cyberspace, the chambers of the Cape Cod mansion. Brutal, faceless powers are after the unlovely manuscript. Perhaps its author's drowning wasn't an accident after all.

For years before the publication of Fatherland, his multimillion-selling debut novel, Robert Harris was an assiduous and illustrious political commentator. Though his subsequent condemnation of the government over the dismissal of Peter Mandelson and the invasion of Iraq could not have been more public or more vehement, his association with New Labour at its inception was, as he himself says, "almost compromising for a journalist". He has often denounced the way modern political leaders insulate themselves from the consequences of their decisions. In The Ghost he makes shrewd use of the time he spent on the campaign trail, riding around in private jets and armoured limousines: an unobserved observer, in fact, not unlike Tiro the slave.

On election night in 1997, Harris, then working for the Sunday Times, was famously the only journalist at Tony Blair's side watching the results come in. With his thick, wavy hair and his characteristic grin, his restless physical energy and eagerness to make a good impression, Adam Lang bears an uncanny, almost unpleasant resemblance to the original, though Harris never actually specifies which political party Lang represents. On the other hand, he makes it pretty clear that Lang himself didn't really care which party he had to join, as long as he could be prime minister.

Cynical, illuminating, both hard-boiled and passionately sensitive, The Ghost is a political thriller, not a satire, nor a veiled attack. Like Harris's first novels, it's set in a world discernibly different from our own. Lang's London is routinely disrupted by terrorist bombs. Lang himself is a failed actor from Leicester, not a failed rock singer from Edinburgh, and he evinces no particular religious convictions; Rycart is decidedly more Michael Heseltine than Robin Cook. While the novel owes its existence, its composition in, apparently, five white-hot months, to Harris's anger at Blair and his administration, the fierce heart of the plot - the great revelation, and the crucial twist in the tail of it - are an imaginative impertinence, an accusation no one could make or take literally. The Ghost is, finally, not about Blair; though it remains an indictment of everything he did and stood for. It's also, and most vitally, intelligent, perceptive and enormous fun.

· Colin Greenland's Finding Helen is published by Transworld