Asiye Guzel no longer wrestles with her "second I" - the internal voice that taunted and confronted her throughout her five-year incarceration in a Turkish prison. "You're naked. Everyone's looking at you!" it mocked, when her torturers stripped her of her clothes. "You're not clean any more, you can't look people in the face," it told her after they raped her. "Face yourself," it urged her as she struggled to tell the truth about her treatment.

Since her release in June 2002, that voice has calmed itself. "If your consciousness is split, then your second 'I' will begin speaking to you. I tried to chase her away, but she was too strong. Now I am conscious of this quality: a person's willpower is their most powerful weapon." This is a fortunate position to have arrived at. Even now, living in Stockholm following a grant of political asylum, Guzel's willpower is her only weapon.

The journalist and activist was arrested in a raid on her home in February 1997. She was 27, just married and working as a reporter on the Turkish newspaper Atilim. "I wanted to play my part in the human rights movement, but it was difficult to make even a small contribution. I took part in the students' democratic movement and I was taken into custody many times. Everyone in the movement knows if they are arrested they are in trouble. I presumed I would be tortured. I took that risk on board," she says evenly.

Guzel was held at the security police headquarters in Istanbul for two weeks, during which time she was tortured and gang-raped. In her political memoir, Asiye's Story, which has just been translated into English, she recounts how she was blindfolded and tied to a chair before her interrogation began. When she asked to be allowed to contact her lawyer and her family, she was laughed at. She was ordered to write a confession. When she refused, she was stripped naked, her arms tied tightly behind her and put through a wooden beam which was then suspended from the ceiling.

"My attempts at breathing turned into another torture. My ribcage was bursting." When her tormenters returned, they pinned her to the ground and raped her, still blindfolded. "I felt a heaviness upon me. My teeth were clenched with the pain. I couldn't resist or move at all, not even get my mind to work. My throat was going to tear apart from screaming," she writes. When the horrible heaviness on me had finished its business, I felt frozen as water turned to ice. Even my wish to die was taken away from me."

Assault by rape may have the same aim as electric shocks, argues Guzel, but it leaves a person specially damaged. "Turkey is a feudal system," she explains, "and women who have been raped are looked on in a different way. Inevitably, women take on this feudal view, however enlightened they may be. So, basically, rape is far more destructive to women."

She documents in her memoir her own battle to articulate what happened to her without shame. The first person she told was Arif, a male colleague who was also in the prison. "It didn't come out suddenly. Knowing I was in a bad way, Arif kept trying to encourage me to talk to him. He had a knowledge of psychiatry."

Telling Arif both lifted and altered her burden, she says. "You feel as though a burden has been lifted off your shoulders but on the other hand he could go and tell somebody else. I hadn't thought that I would let it out. I was going to keep it a secret." But eventually Guzel found the courage not only to speak about her ordeal in open court, but also to write about it. "If I hadn't done it I would have been dead, not physically but psychologically," she insists. "You can't live with a secret like that all your life. If I had not spoken out it would have been as if I was condoning what the police had done to me."

Guzel's manuscript was smuggled out of prison chapter by chapter, and published in Turkey in 1999. One of the first detailed accounts of state-based sexual violence to emerge, it became a bestseller. "It had a big response, especially from women," she says, "because rape and sexual harassment are very widespread there and women would keep their experiences hidden. My lawyers also worked very hard on bringing a case against the police for the rape (unsuccessfully) and a committee against rape was formed. I hope there is more openness now."

Guzel last saw her husband - also a political activist - in the summer of 2002 in a prison hospital, where he was being treated for the debilitating effects of prolonged hunger strike. She had been temporarily released while her case continued. Last October, she travelled to Sweden where she was due to receive the prestigious $8,900 Tucholsky Prize - Salman Rushdie is a previous winner - awarded to writers who show courage when their freedom of expression is threatened.

Two days after the ceremony, her lawyer phoned to tell her that the Turkish court had found her guilty in absentia and sentenced her to 12 years. With the aid of PEN, the Writer's in Prison Committee, she applied for asylum in Sweden, and this summer was granted leave to remain.

Visiting London for a day of talks organised by the English chapter of PEN, she admits she is still getting used to freedom. "Inevitably one's life integrates. I didn't feel very cut off from my life outside when I was in prison because I still had a direct connection with outside life. But recently my life in prison has come back to me, and I am missing the relationships that I had there. I am not missing life in prison."

She says she is still getting to grips with her new life in Sweden. She calls her family, and writes to her husband, who is still in prison. Were there times when she questioned her chances of survival? "From time to time. After I'd told Arif [about the rape], I had a lot of thoughts about suicide. The thing that kept me going was the idea of revenge on the police. They didn't murder me physically but they were trying to murder me psychologically."

Does she feel that, through her own survival and her book, she has achieved that revenge? "Yes," she states defiantly. "You can meet bad things head-on, although there may be moments when one has no hope in life. I believe that every person has a huge strength to resist. The most important thing is not to give up."

· Asiye's Story by Asiye Guzel is published by Saqi books, £7.99. PEN's Writer's in Prison Committee supports and monitors prisoners and campaigns for their release. For further information visit www.englishpen.org.