I almost wrote another book and almost abandoned this

Margaret Atwood

A best-selling and critically acclaimed author, she had been shortlisted for the prize on three previous occasions - for her novels Cat's Eye, The Handmaid's Tale and Alias Grace.

The Toronto-based writer told the Guildhall audience she was unprepared for the award.

"It has been a pleasure to be on the shortlist with such good books and such good sports," she said.

"I'm very honoured to have the prize this year, but really it's about reading and writing.

"There's an unknown writer out there who is writing next year's Booker right now, so good luck to you."

Chairman of the judges Simon Jenkins said of her book, which sees an elderly woman reflect on the events of her life: "It's not a sad book, but it's a sad book. As she says in her conclusion, there would be no stories if there were no journeys."

He told Atwood she was "three times the bridesmaid, now the bride", for winning on her fourth attempt.

In its 32nd year, the Booker offers cash prizes totalling �26,000, and even greater rewards in publicity and sales figures.

The prize is awarded to the best full-length novel of the year and is open to authors from Britain, the Commonwealth and the Republic of Ireland.

Ms Atwood had previously said she was surprised to be nominated.

Booker Prize shortlist

Margaret Atwood, The Blind Assassin Kazuo Ishiguro, When We Were Orphans Trezza Azzopardi, The Hiding Place Matthew Kneale, English Passengers Michael Collins, The Keepers of Truth Brian O'Doherty, The Deposition of Father McCreevy

"I jumped up and down.. I had struggled for months. It had the wrong start. I almost wrote another book and almost abandoned this. But I suddenly got the right person talking," she said.

Japanese-English writer Kazuo Ishiguro - who won the Booker in 1989 for Remains of the Day - was on the shortlist for the third time.

His novel, When We Were Orphans, concerns a detective piecing together the mystery of his parents' disappearance when he was a small boy.

The other contenders included Michael Collins' The Keepers of Truth, about a journalist investigating the death of an industrial magnate, and a tale about the Maltese community in Cardiff by first-time novelist Trezza Azzopardi.

Also in contention were Michael Kneale's novel about a 19th Century priest striving to prove the literal truth of the Bible against scientists, and Brian O'Doherty's story of an isolated Irish village in which all the women mysteriously die.