Don't bother asking for it in bookshops - the hottest book in Turkey probably doesn't even exist. The so-called 'Red Constitution' is so secret that it is said only the Prime Minister and members of the National Security Council have access to it. Its very existence is probably a myth, but this kind of conspiracy theory is a natural product of the culture of censorship and paranoia that swirls around Istanbul's intelligentsia, some of whom spend more time defending themselves in court than sitting behind their desks. There is really no need to imagine a censorious secret constitution - the real one causes enough problems.
Reformed in 2005 to bring Turkey into line with European standards of human rights, the new penal code may be an improvement on its predecessor, yet as one prominent Istanbul lawyer put it to me: 'For every step forwards in Turkey, there are two steps back.' This new code is riddled with what he calls 'black holes', offences designed to catch anyone who mentions one of the many unmentionable issues in Turkey's recent past.
Any literary conversation in Istanbul is peppered with references to a lottery of laws - the unlucky numbers include articles 216, 288 and 301 - under which writers, publishers, journalists and editors are regularly and wearyingly taken to court. It sometimes looks as if there are only two kinds of writers in Turkey: those who have been to prison for their work and those who haven't.
When Orhan Pamuk was charged last year over remarks he made about the numbers of Kurds and Armenians killed in Turkey in the last century, he said that at least he could now hold his head up among his more inflammatory colleagues.
Having decided early on to concentrate on writing rather than go looking for trouble, Pamuk was a stranger to the legal system and his trial last December for 'denigrating the Turkish state' caught the attention of the world's media. This attention, and the support of free-speech advocates, may have helped Pamuk get off, but it played into the hands of ultra-nationalists who claim that liberal writers are in the pay of outside forces.
The tall, bespectacled Pamuk has a donnish, distracted air. When I track him down to the kind of literary cafe that British writers can only dream of - hidden up three, tall flights of stairs in a seedy apartment block behind a locked door; walls of caricatures wreathed in the smoke of a thousand Turkish cigarettes - he is genial, but unwilling to talk of his recent experiences. Pamuk has told friends that he is caught between two poles. On the one hand, it his duty to write. On the other, he believes that authors must engage with the society around them.
Most Turkish writers wrestle with this contradiction. They are caught, like Turkey, between powerful opposing forces. At Istanbul, where Europe gazes anxiously across the Bosporus at Asia, Turkish nationalists, Europhile modernisers and Islamists fight proxy battles through the writings of those who dare to question the status quo.
The écrivain engagé, last seen in Western Europe in 1968, is a flesh-and-blood reality here. When brilliant young novelist Elif Safak, who has Turkish roots but now lives in Arizona, first wrote in English, there was outrage back home. Worst was the fact that she began spelling her name phonetically, 'Shafak', for Americans, and omitting an accent. 'You lost the dot!' screamed her detractors in Istanbul. Safak is also at the forefront of Turkey's gender war.
When her latest book, Baba the Bastard, came out this month, some bookshops refused to stock it, not only because of the word 'bastard', but also because the pomegranate on the cover resembles a vagina. 'It is always difficult to overcome the sexual taboos in this society and that is a subtle silencing mechanism for writers,' she says.
Safak sees this level of political engagement as both the blessing and the curse of Istanbul's intelligentsia. She has noticed that her interviews in the United States tend to revolve around her style and influences, while here they're more likely to take in the war in Iraq, oil prices and fundamentalism. She finds this frustrating, telling me over dinner in a restaurant high above the Galata Bridge that while writers have a key role to play in exploring Turkish identities, they must not become politicians: 'The literary person needs to belong to no community at all - you need to live within your novel.'
But in today's Istanbul, this may not be an option. When even such unworldly figures as Pamuk are dragged into the courts, there is little hope of genuinely free discourse. As Turkey struggles towards EU membership, something has to give, and many writers I spoke to believed things would get easier.
For now, though, writers are on the front line between competing orthodoxies. We may never read the really exciting Turkish novels of 2006, because they may never get written.
· Jonathan Heawood is director of English PEN
