Hirsi Ali doesn't sound like an embattled activist. Her quiet, fluty voice matches a fine-featured face, which peers with calm resolve from the cover of her memoir, Infidel: The Story of My Enlightenment, published by Simon & Schuster and Free Press this month. But her language is anything but delicate. Hirsi Ali has called the Prophet Mohammed a 'tyrant', a 'pervert' and a 'paedophile', for counting a nine-year-old among his nine wives.

She writes in the book: 'When people say that the values of Islam are compassion, tolerance and freedom, I look at reality, at real cultures and governments, and I see that it simply isn't so. People in the west swallow this sort of thing because they have learned not to examine the religions or cultures of minorities too critically for fear of being called racists.'

For Hirsi Ali, Islam is inimical to individual rights because it calls for the individual's unquestioning submission to God. Hirsi Ali argues that Islam enforces an unyielding hierarchy - leading down from Allah, to the Prophet, to religious leaders and then to the father - that leaves no space for individual freedom. Hirsi Ali bats aside the suggestion that this account could equally apply to other monotheistic religions, which demand obeisance to a single God.

'Judaism and Christianity have gone through a long history of enlightenment and reflection. But the Islam that we see today tends towards the 7th century. Islamic reformists throughout the centuries have been harassed and exiled and killed.'

Her view of the Koran as a rubber stamp for violence against women provides no room for Muslim feminists who believe Islamic theology can be rescued from patriarchal custom.

'Religion is an expression of culture, and Islam is an expression of desert Arab male culture. Being an atheist - believing that religion was created by man and not the other way round - we have to recognise that we can't separate the two.'

Hirsi Ali was born in Somalia in 1969, immediately prior to the military coup of Siad Barre, which vanquished the democratic hopes of the newly independent country. Her father, Hirsi Magan Isse, was a Columbia University-educated dissident politician, forced into exile after Barre's ascent. The family moved to Saudi Arabia, where Hirsi Ali was reared on myths of a global Jewish conspiracy.

'When we opened the tap and no water came from it, our neighbours would say: 'The Jews have done it. They want to dehydrate us.' When it rained, we got that from God's blessing. But if there were fires, if there were floods, if there were diseases, it was always caused by the evil Jews.'

The family received official warning to leave Saudi Arabia after the regime got wind of Magan Isse's insurgent activities. Hirsi Ali spent her youth moving between countries as political circumstances fluctuated - to Ethiopia, then to Kenya, back to Somalia and, finally, to Kenya again.

Magan Isse was determined to exempt his daughter from the tradition of ritualised female genital mutilation. When Hirsi Ali was five, however, her grandmother arranged for the operation without her father's knowledge.

'As a child it's something that you're proud of. You know that it happens to everyone else and if it doesn't happen to you, you'll be isolated by the other kids.'

Despite his distaste for female 'circumcision', Magan Isse was proud to offer his daughter up for an arranged marriage 17 years later, when a distant cousin arrived from Canada looking for a wife. 'In the Somali tradition, an arranged marriage is an honorable one. It's an obligation of the father to arrange marriage for his children,' Hirsi Ali says.

On the way to Canada to meet her husband, Hirsi Ali was to spend a few days with relatives in Germany. Once in Germany, however, she took matters into her own hands, fleeing by train to the Netherlands to seek refugee status.

'I felt deep in my heart that whatever had happened - even if I had gone to Canada - I would have sabotaged the marriage.'

Hirsi Ali was granted asylum after three weeks, a processing period unheard of today. She learned Dutch while working in unskilled jobs, soon becoming a translator in hospitals and shelters for battered women. She was shocked that the abuse of Islamic women was also rife in Amsterdam. She was similarly taken aback by the state's refusal to interfere in what they regarded as 'cultural matters'. Muslims account for only 5.5 per cent of the Netherlands' population but, according to Hirsi Ali, make up over 50 per cent of the women in Dutch refuges.

Completing a political science degree at Leiden University, Hirsi Ali became grounded in the Enlightenment thinkers who anchor her essays - Baruch Spinoza, Immanuel Kant and Voltaire.

'The years at university were the happiest times of my life. It was an environment where reason ruled. Everyone is civilised and kind and happy. It's just an environment where civilisation reaches its peak.'

After graduating, Hirsi Ali became an immigration researcher at a think tank aligned to the left-of-centre Labour Party. The September 11 attacks occurred two weeks into her stint, triggering her loss of faith.

'I was pushed to think clearly about whether I was on Bin Laden's side or not. I started to think, 'Do I really believe in this God who demands blood and mayhem?''

Hirsi Ali became a sought-after media spokesperson on Muslim affairs. Asked on television for

her response to the far-right politician Pim Fortuyn's description of Islam as a 'backward religion', Hirsi Ali conceded he had a point.

She argued that the Dutch multicultural programme was complicit in the abuse of women because it gave Muslim communities autonomy while funding 700 Islamic schools, clubs and mosques. Hirsi Ali broke ranks with the left, shifting her allegiance to the centre-right VVD Party (People's Party for Freedom and Democracy).

'It started with the emphasis that the Labour Party was putting on migrants as a group. It was, 'You want to discuss the rights of individual women who are abused but the whole group of migrants must integrate and find jobs first. Then we will attend to the grievances of women.' The VVD Party, on the other hand, was stressing individual rights and obligations. It was much easier to defend that position than just to lie back and hope that one day the lives of all migrants would be okay and thereby that of women.'

Despite not having planned a political career, Hirsi Ali became a parliamentary member in January 2003.

'I was planning to be an academic. But there's just a moment when you have to take part in politics if you feel that other people are not doing the right job. I just thought everyone was blind to the situation of Muslim women. I couldn't just stand on the sideline and start pointing out that everyone was getting it wrong. I thought I'd do it for four years. Within two years I had managed to convince everyone there was something terribly wrong in Holland with the living conditions of Muslim women.'

Gay demagogue Fortuyn - who was outraged by Muslim intolerance of homosexuality - was assassinated by a Dutch animal-rights activist in May 2002. Then came the murder of filmmaker Theo van Gogh in 2004, following his collaboration with Hirsi Ali on a short film, Submission - the first of a series they planned to produce together.

The film depicts four semi-naked Islamic women, half-clothed in traditional garb. The Koranic verses that allegedly authorise violence against women are written on their lacerated flesh and they describe the physical abuse they suffer from their husbands.

Van Gogh was stabbed and shot by a young Moroccan-born jihadist while cycling to work in Amsterdam. With his knife, the killer attached a letter to van Gogh's corpse assuring Hirsi Ali she would be next. Since becoming a public figure, Hirsi Ali had had round-the-clock police protection. She travelled in armour-plated cars and was trailed bodyguards.

But van Gogh - who had used epithets such as 'goatf*****' and 'pimp' to describe the Prophet since the early 1990s - didn't feel he needed protection.

'He said he didn't believe in the capabilities of the people who would be protecting him and he would

be losing his privacy,' says Hirsi Ali. 'He thought it was different in my case because I had become an apostate and there were so many examples of apostates being killed by Arab men.'

In May last year, Hirsi Ali was rounded on by a member of her own political party. Following allegations on a television programme that she lied about her identity to win asylum in 1992, the Dutch immigration minister, Rita Verdonk, declared Hirsi Ali's passport invalid. At the urging of Dutch refugee workers, Hirsi Ali had claimed that she was fleeing the civil war in Somalia rather than an arranged marriage. When claiming asylum, she also lied about her date of birth and changed her father's name, Magan, to Ali, in order to hide from her family - fabrications that she had long spoken publicly about.

Verdonk retracted her decision after touching off a public uproar but Hirsi Ali had already decided to resign from parliament to take up a position at the American Enterprise Institute (AEI) - a Washington-based neo-conservative think tank.

'I had accomplished in parliament what I wanted to do, which was put the suffering of Muslim women on the country's agenda. For now, I'm only interested in writing and making films, developing this tension between the Muslim and western mind.'

Hirsi Ali says she is happy to be living in the US. 'Whatever your feelings on the subject, the United States is the leader of the free world,' she writes in Infidel. 'By taking my ideas to the United States, I don't feel that I'm in any way selling out.'

Hirsi Ali will soon start filming Submission: Part 2 - a project AEI has been fully supportive of. 'I gave them a proposal, in which I mentioned how I was going to represent the Prophet Mohammed in New York and have him talk to a number of western thinkers, and they said, 'No problem.''

She acknowledges the irony of being a feminist activist employed by an affiliate of the conservative US Republican Party. 'It is ironic but I talked to different think tanks and it was only the American Enterprise Institute that said, 'We welcome controversy'. [They said] I would have total intellectual freedom.'

The identities of her collaborators on Submission: Part 2 will remain anonymous. 'After van Gogh's death, I've learned a lesson and that is: you have to make a film without putting the identity of the people out there.

'You have to be smarter than the killers.'

Infidel: The Story of My Enlightenment, by Ayaan Hirsi Ali, is reviewed on page 6 of The Review.