Today The Observer follows in the literary tradition made famous by Charles Dickens, Sir Arthur Conan Doyle and, latterly, Alexander McCall Smith, and begins the weekly publication of a major new work by novelist and screenwriter Ronan Bennett, author of the acclaimed books The Catastrophist and Havoc, In Its Third Year. A tense political thriller set in St Petersburg in 1914, Zugzwang will unfold over 29 weeks.

It's a prospect that both intrigues and daunts Bennett, who describes himself as a slow writer - each of his previous novels has taken five years to complete - and who admits that he is 'in the dark' as to exactly how the novel will progress. 'One of the big thrills as a writer is the way people respond to your work,' he says. 'What's exciting about a deadline is what will emerge in the writing.'

Zugzwang, a chess term used to describe a helpless position in which a player can only make his situation worse by moving, begins in dramatic fashion with the murder of a newspaper editor. Subsequently, we hear of a spectacular chess tournament and one of its brilliant, troubled participants. Soon, we are caught up in a world of murder, detection, intelligence and counter-intelligence. It was the challenge of describing this turbulent milieu - with its parallels to contemporary life - that most appealed to Bennett. 'In the past couple of years I have thought a lot about intelligence, and how it is used to justify everything from the invasion of sovereign states to internment without trial.'