A Most Wanted Man, by John le Carré

When the Cold War ended, it seemed for a time that a whole genre of novels had been wiped out with it. The epic struggle between the West and the USSR was over, removing the favourite subject-matter of novelists such as Len Deighton and John le Carré. Where would they go? What would they do? Martin Cruz Smith, author of Gorky Park, found a rich seam in post-Soviet Russia, as have new writers such as Alex Dryden, whose acclaimed first novel Red to Black is an urgent warning about the global ambitions of Moscow.

Le Carré has gone in a different direction. In The Constant Gardener, he turned to Africa and found a new adversary in global drug companies using the poorest people in the world to test new drugs. But the decades of Cold War espionage keep drawing him back, and the friendship at the heart of Absolute Friends took him into the old East Germany, territory he mastered a long time ago.

That novel ended, not entirely successfully, with a collision between le Carré's old spies and the post-9/11 world; its mood shifted abruptly from elegiac to enraged, abandoning the ambiguities which were a feature of his earlier work. His new novel, A Most Wanted Man, plunges into the midst of the war on terror and the moral landscape it has created.

Its protagonist is a disturbed young man who arrives illegally in Hamburg after spells in prison in Turkey and Russia. Issa is Chechen, but doesn't speak the language; he is a Muslim, but doesn't know the difference between Sunni and Shia; he is on the run, but has an unexplained stash of cash. He says he is seeking asylum and wants to train as a doctor, but Western intelligence agencies believe he is a dangerous terrorist.

The sarcastic double meaning of the title – Issa inspires passionate love as well as the close attention of several intelligence services – is a signal that le Carré is, if anything, even angrier than when he wrote Absolute Friends. His spies operate in a murky, recognisable world in which the Russian military casually committed war crimes in Chechnya and senior KGB men spirited their ill-gotten gains into secret bank accounts.

Issa is the beneficiary of one of those accounts, set up in an English bank which used to have its headquarters in Switzerland until it relocated to Hamburg. Its head is Tommy Brue, son of the founder and a typical le Carré character: educated at a public school in Scotland; overshadowed by his dominating father; about to be sidelined by his socially ambitious second wife. When Issa enters his life, he is a failure in the unspectacular way of men of his class and generation.

Tommy falls in love with Issa's lawyer, Annabel Richter, a young woman who has abandoned her own privileged background to work in a law centre. These two isolated people join forces to protect Issa while they try to persuade him to claim the fortune which is legally his. At the same time, Issa is being watched by Gunther Bachmann, a maverick spy in the German intelligence service who wants to use him to catch a bigger fish: a "moderate" imam who is suspected of channelling funds to terrorists.

Bachmann is one of le Carré's good guys, nothing much to look at and distrusted by his superiors, but clearly the novel's moral centre. He isn't too worried by an emaciated Chechen boy who has been tortured to the edge of reason, but his humanity isn't shared by rival spooks from his own service, the CIA and British intelligence. Hardened by 9/11 and other atrocities, they work on the assumption that every suspect is guilty and don't care too much about their methods.

This is a slow-moving novel, with characters who feel like flatter versions of people who have appeared in John le Carré's earlier books; Annabel, in particular, is more a combination of gestures and attitudes than a fully-drawn character.

It is fiction as polemic, a vehicle for le Carré's passionate hatred of what Western governments have done in the struggle against Islamist terrorism. Instead of ambiguity and moral dilemmas, it is driven by a self-righteous certainty which turns the novel into a surprisingly dull read.

Joan Smith's novel 'What Will Survive' is published by Arcadia