'Personal and political'

They say favourites never win, but Hilary Mantel proved sceptics wrong when, at a ceremony at London's Guildhall onTuesday night, she won the 2009 Man Booker Prize for Wolf Hall, her acclaimed novel about Thomas Cromwell's rise to power in the Tudor court of the 1520s. According to the bookies Ladbrokes, more than 80 per cent of all Booker Prize wagers were placed on Wolf Hall, making it the most popular book in the £50,000 (Dh292,000) award's 41-year history. James Naughtie, the chairman of judges, called it "a thoroughly modern novel set in the 16th century. Wolf Hall has a vast narrative sweep that gleams on every page with luminous and mesmerising detail."

A delighted Mantel told the audience that although the novelist Peter Carey once compared winning the Man Booker to being in a train crash, "at this moment I am happily flying through the air". After the ceremony, Mantel laughed off suggestions that the persistent chorus predicting her win filled her with false hope that it might happen. "Having been a Booker judge [in 1990, the year AS Byatt won for Possession], I know that absolutely anything can happen in that final meeting. I don't think people appreciate how very tense it can be for the judges as well as the authors. You go in to fight for your book, and if you don't get your way you come out thinking: 'Did I do it right? Could I have said something different?'

"I have vivid memories of the final judges' meeting when I was a judge. I just know to take nothing for granted. I never for a moment thought being the favourite would weigh with the judges. In fact, I thought it might work in the opposite way. I thought they might get fed up with being told what to do." Mantel, 57, published her first novel, Every Day Is Mother's Day, in 1985, after she had returned to Britain after living in Saudi Arabia for four years. Since then, she has written nine novels, including A Place of Greater Safety (set during the French Revolution) and A Change of Climate, as well as a memoir, Giving Up the Ghost. She lives with her husband in Woking, an unglamorous, far-flung suburb of London, on the top floor of a converted Victorian asylum.

She conceived the idea for Wolf Hall in the 1970s while working as a social worker in Botswana, but didn't feel mature enough to attempt writing it. "Sometimes you just have to put the idea away. It has to grow. You have to grow - you have to grow up. I couldn't back then have written a book about a seasoned, hardened political campaigner in his 50s. But now I'm a seasoned, hardened literary campaigner in my 50s, so I can do it!"

Kingsley Amis, who won the Booker for The Old Devils in 1986, spent his winnings on new curtains. Mantel says she plans to spend hers on "living". "It's earnings. That may seem a very cold way of looking at a major award, but if you cost out what an author earns per hour is far, far less than the minimum wage, especially when you begin, and I've been writing since 1974 and published since 1985. The return is not great. The money from prizes, welcome though it is, must just be aggregated. It must pay the mortgage, which authors have to do on their humble garrets."

Mantel's love for the Tudor period and its characters is so intense that she has already started work on a sequel. "For obvious reasons, I don't want to talk about a book I'm only halfway through writing because books can surprise you, but the sequel to Wolf Hall will be called The Mirror and the Light. We leave Wolf Hall in 1535. It's the evening of Thomas More's execution and Henry VIII is going on his holidays. I'm going to take up the book that autumn, when the royal party are at Wolf Hall in Wiltshire with the Seymour family - so for anyone who knows their Tudor history, alarm bells will already be ringing. The story will follow Cromwell's continued rise until he falls from grace and is executed in the summer of 1540."

She admits she hasn't made much progress with it. "What I've got at the moment is a huge box full of notes. Some of it strings together. Some of it is waiting to fall into place. So I don't know how long it's going to take to finish. How long is a piece of string? "Since Wolf Hall was published in the spring, I've been doing a lot of festivals, a lot of readings and so on. You can't work on a big fact-based book in a broken-up fashion. You need time to concentrate. I hope that time will come later this year."

Mantel has written at length about her poor health, especially the endometriosis from which she suffered in her 20s and which was for years - and with horrific results - misdiagnosed as depression. "I have had a great many health problems over the years. I don't make any secret of it. It has influenced my production of books and the rhythm with which I've written. I might be a couple of books on if I'd had better health. But I think that was one of the things about Wolf Hall. A book like that takes tremendous energy to push through. I hadn't got to the point where I felt I could put that energy behind it. Finally I did."

Was she conscious while writing Wolf Hall that it might be interpreted as a commentary on the contemporary political scene? "There's no deep, obscure allegory in the book about contemporary events. I think history is worth writing about for its own sake. We do a disservice to the dead if we use them as pasteboard figures through which we enact our contemporary dramas. Having said that, the subject matter remains relevant because the basic facts of the political process don't change. The exercising of power, the business of obtaining power, how it's lost - we're still in Machiavelli's world, which is where Thomas Cromwell was."

In the novel, Cromwell declares: "The fate of peoples is made like this, two men in small rooms. Forget the coronations, the conclaves of cardinals, the pomp and processions. This is how the world changes." Mantel says: "What a novelist tries to do is junk the hindsight, junk the moralising, go back there and walk the road again. And that's really what I want my reader to do. I want them not necessarily to like Cromwell, not necessarily to sympathise with him, but I want them to walk in his shoes and see how the realities of Tudor politics looked from where he stood. I'm operating, if you like, on the frontier of the personal and political."

Wolf Hall is published by Fourth Estate.