Diary - Ronan Bennett

Since the run-up to the invasion of Iraq I've had intelligence on the brain. And since then I've bee

The first chess book I owned - Irving Chernev's The Most Instructive Games of Chess Ever Played - was given to me in 1978 by the late Larry Grant, a gentle, hulking, stooped, bearded giant. I was in Brixton

Prison, remanded on conspiracy charges, and for a time Larry was my solicitor. It was my introduction to the logicians and conjurors - Morphy, Lasker, Capablanca, Alekhine, Botvinnik - who are revered by chess fans the world over. Larry disapproved of my initial enthusiasm for Alekhine - Larry was Jewish and Alekhine, he told me, was a notorious anti-Semite. I lost the only game I ever played against Larry. I was black and Larry played a King's Gambit. I got through the first few moves OK but was pretty much in the dark after that. I'm as mediocre a player now as I was then, but I remain fascinated by the precision and ambiguity of chess.

Larry Grant did work for the National Council for Civil Liberties (as Liberty used to be known) back in the days when Harriet Harman and Patricia Hewitt, the double act who ran the organisation, were still interested in the rights of individuals confronted by state power. Indeed, so concerned was Harriet about the way our trial was being conducted - the "Persons Unknown" trial took place in late 1979 at the Old Bailey - that she attended court to listen to defence challenges to the legality and morality of the Crown's efforts to have the jury panel vetted by the intelligence services. It was jury-tampering by the state but we lost the argument and the vetting went ahead, though only on condition that the intelligence was shared with the defence. It is the only time I have ever seen an intelligence document, and it was pitiful. This juror drank in a pub frequented by criminals; that juror's brother-in-law was a suspected burglar.

In the past couple of years intelligence has been used to justify everything from the invasion of a sovereign state to torture and internment without trial. Had Bush and Blair not been able to claim they had compelling intelligence would war have been possible? "Flawed" does not do justice to what they palmed off on us. It was as threadbare as the document the Crown passed to us at the Old Bailey all those years ago. Writers have to follow their obsessions, the things that gnaw at them, that lodge in their brain, and since the run-up to the invasion of Iraq I've had intelligence on the brain. And I've been trying to think of a way to write about it in a novel. But how?

Last summer I was glancing through an old biography of Lenin, by David Shub, and learned two things. First, Lenin was a chess player. Second, the Okhrana - before 1917 one of the world's most sophisticated secret police forces - had penetrated the Bolsheviks to such a degree that Lenin was forced to convene a meeting in 1914 to discuss allegations that the leader of the Bolshevik delegation in the Duma was a spy. Half the senior party figures present were Okhrana agents. Which makes you wonder: if the Bolsheviks were so heavily infiltrated how did they come to power? It's a question we might ask of MI5 today in relation to Irish republicans. Stakeknife and Denis Donaldson notwithstanding, Sinn Fein is poised to become Ireland's largest political party. We could ask about the July bombers. About Jean Charles de Menezes. What do intelligence agencies do? Next time I see Harriet Harman I will ask. I suspect any answer would be in similar vein to the one Chris Mullin offered when I asked him about the detainees in Belmarsh: "9/11 changed everything, Ronan."

Chess, intelligence, prison, anti-Semitism, history, who and what you are and where you've been - in writing fiction everything goes into the mix. By the end of November I thought I'd found the first couple of moves for

the novel, and a title - Zugzwang. Set it in Russia in 1914 during another so-called clash of civilisations (pure Russian civilisation against Jews bent on world domination). There are revolutionaries and reactionaries, advocates of war and peaceniks, spies, infiltrators and double agents, idealists and cynics . . . and chess players. The BBC's adaptation of Bleak House got me thinking about doing it as a serialisation. I sent Roger Alton, the editor of the Observer, the 4,000 words I'd written. He liked it and kicked off with a double instalment, with watercolours by Marc Quinn, in the Observer's Berliner launch issue. I'm a move or two ahead of myself and I know where I'd like the story to go, but really I'm making it up as I go along. Very like the game I played with Larry.

Ronan Bennett's most recent novel is Havoc, in Its Third Year (Headline)