Edwina Currie, whose sensational diaries are published today, is the latest public figure to bare her soul in print.

Christen Pears reports on the phenomenon of celebrity autobiography.

THERE were plenty of people choking on their cornflakes on Saturday morning. Opening a newspaper and discovering that John Major, a man so sensible he tucked his shirt into his underpants, had been having an affair with the outspoken Edwina Currie was enough to make anyone splutter. Who would ever have imagined it?

As a nation, we've been shocked by the revelations, both fascinated and repelled by the details of the four-year relationship that had remained a secret until the serialisation of Mrs Currie's diaries in The Times. The story has all the ingredients of one of the former MP's steamy parliamentary novels. It has done untold damage to the reputation of the former Prime Minister, but will, no doubt, do wonders for sales of Mrs Currie's book.

She has reportedly been paid around £200,000 for her diaries by publishers, Little, Brown - small change compared to HarperCollins' £2m deal for David Beckham's memoirs, due to be published next autumn. But the former MP looks set to make over £1m from sales. In fact, cynics say money is the main reason she has chosen to reveal her affair with the not-so-grey man of politics.

Mrs Currie has, of course, vehemently denied this was her motivation. "If that had been the case, I would have done it when he was Prime Minister," she told the BBC in her first interview yesterday.

And it's true. Revealing she had enjoyed a four-year affair with the PM would undoubtedly have brought down a government already beset with problems, many related to the sexual infidelities of some of its most senior ministers. Mrs Currie could really have cashed in, but she waited.

Asked why she chose now to publish her diaries, she said: "The picture that had been painted of those years, particularly in the 1980s, was a little limited and I had the answers to an awful lot of questions. I hung onto those answers until they could do no more damage and it then seemed to me to be appropriate to set the picture straight."

"I feel cleansed - I have been carrying this secret for a very long time on other people's behalf," she added.

Her comments ring true with John Given, a lecturer at the University of Northumbria, and an expert on the way people shape their own sense of self.

"Traditionally, identity has been given to us by our family and community but, in the contemporary world, with increasing globalisation, people are having to make it up for themselves," he explains.

"A typical example would be when someone is dying. They want to set the record straight with friends and family. In a way, Edwina Currie is doing the same thing - just in a more public way.

"When someone is telling their story, they talk about the things that are on their minds. They base it round key events or crises. That may be a death or an accident or, in the case of Edwina Currie, the end of an affair.

"Some people might say she's just done it for the money but, at the end of the day, she has been given an opportunity to tell the story of her life and this is obviously what's important to her. She clearly feels she has to tell people her side."

Kiss and tell is nothing new but, over the last year, a host of celebrities have exposed their innermost secrets to the reading public - often in multi-million pound book deals and sometimes in a sensational manner.

Last month, in a joint autobiography with her sister, Nicole Appleton revealed she had aborted Robbie Williams' baby following pressure from her record company and All Saints bandmates. In his autobiography, Manchester United captain Roy Keane admitted he had deliberately smashed the knee of another player.

Between now and November, Ulrika Jonsson, Lulu and Ruby Wax will be among the big names to bear their souls in print. There's already frenzied speculation as to what Ulrika will say about her affair with Sven Goran-Eriksson.

It seems we can't get enough of celebrity secrets, the more sordid the better. The publication of the latest volume of Tony Benn's diaries would usually attract huge amounts of media attention, particularly when it includes a series of stinging attacks on Tony Blair and New Labour. But it has been overshadowed by Mrs Currie's parliamentary diaries - largely because of their salacious content.

Nicholas Clee, editor of The Bookseller magazine, believes the trend is being driven by society's wider obsession with fame. He says: "There have always been star autobiographies but, over the last couple of years, they have become a publishing fashion and I'm sure there will be many more.

"The book industry is dominated by huge conglomerates and chains. They want to sell as many books as they can and one way to do that is if the author is a star. But these days, we're so used to reading about celebrities, the only way a book is going to make a really big impact is if there are certain exciting revelations in it. There has to be a reason to buy the book above what we've already read in the press and that is going to lead to people revealing more and more about themselves - no matter how shocking."

Clearly, some people have more to say than others and for every bestseller, another will end up remaindered. Billy, Pamela Stephenson's gritty biography of husband Billy Connolly has now sold 1.3 million copies but Anthea Turner barely managed to sell 500 of her memoirs.

Edwina Currie undoubtedly has an edge because everyone has been so surprised by the news of her affair and, of course, we have always been fascinated by the heady mix of politics and sex.

Since the Profumo scandal of the 1960s, many high-profile MPs have been exposed, from Cecil Parkinson to David Mellor, Paddy Ashdown to Piers Merchant. Whatever the reasons behind such behaviour, the UK media ensures it is exposed, unlike France where strict privacy laws and a totally different attitude to sexual infidelity allowed President Mitterand to keep a wife and a mistress during his time in political office, something which would be unthinkable here.

Political commentator Chris Moncrieff says: "There is an equivalent of the Mile High club in Parliament of people who want to do it on the Woolsack. No one knows whether it has actually been achieved though.

"But people have certainly had sex in the Press Bar and on the terrace at night. Indeed, the only thing that is surprising about John Major and Edwina Currie is that they managed to keep it secret - Westminster is full of gossip all the time."

* Edwina Currie, Diaries 1987-1992, £18.99, is published by Little, Brown today.