Lisa Appignanesi has successfully led a group of high-profile UK writers in a campaign for free speech. But their work is not over, she tells Louise East.

It seems that several different women share the same unusual name. Surely Lisa Appignanesi, prolific author of mass-market thrillers can't be the same Lisa Appignanesi who was deputy director of London's Institute of Contemporary Arts (ICA), or the Appignanesi who pens academic texts on everything from cabaret to Sigmund Freud? Then there's the memoirist Appignanesi; the free speech campaigner Appignanesi, and even a Lisa Appignanesi who will open the Arts Council's Critical Voices series in Dublin tomorrow.

Yet they're all one and the same Lisa Appignanesi; a Renaissance woman in the European mould, who looks remarkably petite and unhurried for someone who does the work of seven.

When we meet at her house in north London, it is exactly a month since Tony Blair's government lost their fight against the House of Lords' amendments to the Racial and Religious Hatred Bill, and Appignanesi is jubilant still.

As deputy president of English Pen, she pulled together a high-profile group of writers including Ian McEwan, Monica Ali, Philip Pullman and Salman Rushdie to campaign relentlessly against what they saw as a chilling infringement of the right to free speech.

"People started off thinking this was a good thing," explains Appignanesi. "The British are, on the whole, nice people. They don't want to make people feel insulted. But this wasn't quite what it seemed. This was about being allowed to criticise religious practice, power and authority."

In its original, un-amended form, the Bill would have made "abusing" or "insulting" religion a criminal offence. In other words, had it been passed, Father Ted, The Da Vinci Code and The Satanic Verses could all have been in the dock.

"It's not just about being allowed to air criticism," Appignanesi points out. "Such criticism is the very matter of literature . . . It would have ended up with publishers not publishing books which named any number of religious items, simply because they feared prosecution."

The crucial amendments passed in the House of Lords mean that criticism is now a criminal offence only if it "intends" to stir up religious hatred.

"After all, people take offence very easily," says Appignanesi dryly. "I take offence as soon as I step out of the house. Is the government going to take action for each and every time I'm offended?"

That the parliamentary battle in Britain was played out against a wider crisis of free expression in the shape of what she refers to as, "the Danish cartoon wars" is not lost on Appignanesi.

"English Pen is going to launch a commission investigating what people think the parameters of free speech should be in a society which is plural and has people of many faiths living together. Such is the speed of communications now, anything that is said here has repercussions in places where the context is very, very different."

Nor is she blind to the ironies of a cause in which posts about the jailed Holocaust-denier David Irving share website space with those supporting the writers on trial in Turkey.

"Pen's is a very Voltairean stance," she says wryly. "In that while we despise David Irving's complete betrayal of historical fact and don't agree with his holocaust denial, we do believe he should have the freedom to express these views. They are best countered on paper; with argument rather than in court. I don't think anyone at English Pen thinks that freedom of expression is totally absolute," she says.

"One could say that learning how to live in a society together is the best form of restriction on the offensive kinds of expression. But when legislation comes from above, in other words, criminalises speech, that's something else, and we have to be very wary."

AS APPIGNANESI HERSELF acknowledges, it is no accident that free speech is a cause close to her heart. Born Elsbieta Borensztejn in Poland in 1946, Appignanesi's parents were Jewish, yet they managed to pass as Catholics and lived in hiding for the duration of the war. The family moved to Canada when Appignanesi was five and her first spoken language was French. At home, Polish and Yiddish were spoken and it was English in which she learnt to write.

"My sense of what makes power work, of how people who have it don't like to let it go and how it impacts on the lives of those who don't have it . . . I think I did learn that from my parents," she muses. "It seems to me that you need to have free expression or else you can't criticise these things. You can't explore them."

In her brilliant 1999 memoir, Losing the Dead, she describes how her father on his death bed imagined himself to be facing SS interrogation, although in life he never talked about his experiences under the Nazis.

"I wanted to investigate this parental past which was freighted with rather heavy history," she says.

"I wrote about the way in which their story had, perhaps unconsciously, impacted on us children and on the next generation. I was trying to un-pack those things. Why was it, for example, that my mother actually preferred being mistaken for Christian?"

As a teenager, Appignanesi herself had little time for her Jewish roots, marrying an Italian Catholic at the age of 20. Neither the marriage nor Appignanesi's disinterest in her roots lasted. Although she remains a secular Jew, she studied the Nazi period and the Jewish experience extensively as an academic and returns frequently to the subject in her memoir and her novels.

Having moved to Britain as a post-grad student, she worked as an academic until 1980 when she joined the ICA, later becoming its deputy director. In the 10 years she spent there, the ICA increasingly earned a reputation as an intellectual hot-house where new ideas bred and flourished.

"One of the great things about the ICA was that you had a mixing and mingling between the forms and between so-called high culture and low culture," she says, laughingly recalling Jeffrey Archer and Salman Rushdie sharing a platform.

"That's very much what the 20th century has been about. If you think of all the greats of the 20th century, most of them learnt from popular culture or used it in some way."

When she left in 1990, it was to work full time as a writer, and in 1991, inspired by her genre-bending experiences at the ICA, she published her first crime novel, Memory and Desire.

"I was drawn to the notion that you could write popular fiction, which people like to read, and within it, put quite a lot of analytical stuff," she says of her seven subsequent novels. "Also, I'm not a great writer. I'm never going to be Proust; I don't have the flair for language. So I decided I should do what I can do well and it seemed to me I could write thrillers because I read them."

ALONGSIDE HER NOVELS, she publishes non-fiction, including a well-received biography of Simone de Beauvoir and Freud's Women, the book she co-authored with her partner, Cambridge historian John Forrester ("We argued over footnotes").

When her campaigning work eases off, she will return to work on a book of cultural history, Women and the Mind Doctors. "It's a history of all the 'psys' - looking at the way symptoms and history seem to coalesce at given periods. Now, for example, we have a wave of obsessive compulsive disorder; why is that?"

In the rambling house where she and Forrester live, Paula Rego prints adorn the kitchen walls and in the downstairs loo, Appignanesi's certificate declaring her a Chevalier of the Ordre des Arts et des Lettres of France hangs alongside numerous photos of her children, film-maker Josh Appignanesi and student Katrina Forrester.

When Josh made his first feature, Song of Songs, last year, Appignanesi agreed to the house being painted in funeral shades of brown and used as a set, so long as it was transformed back again by the time she returned from holiday. Much to Appignanesi's surprise, the film's subject matter turned out to be the Orthodox Jewish community. "I was astonished. But I guess all children are interested in what their parents have left out."