The casual newspaper reader could have been forgiven for feeling a little confused by the end of last week. The "real story" of "Ulrika's men" was splashed all over the front of the Daily Mirror; the Mail claimed to have the lowdown on John Birt. The Cheryl Barrymore bandwagon was getting ready to roll, just as the Edwina Currie affair had died down. Everywhere you looked, there was another celebrity with a story to spill.

Except that everything was not quite what it seemed. The Mirror's "Ulrika Exposed" spread was a neatly timed spoiler timed to run just before the start of the Mail titles' expensive serialisation of the TV star's autobiography. And the Mail's double-page spread on Birt's BBC years was a similar attempt to knock the wind out of the sails - and the sales - of the Times group's deal to publish extracts from the memoirs of the former director-general.

Serialisations are big business, and this autumn there appear to be more around than ever. By far the most sensational was Edwina Currie's explosive revelation of her affair with John Major, but barely a day has gone by without another set of political diaries or celebrity memoirs hitting the newsstands.

At the front of the queue, with an apparently limitless chequebook, has been the Daily Mail, which at one point last week was running two serialisations in the same paper - the Archer diaries and the memoirs of former Coronation Street actor Amanda Barrie. The serialisation of Ulrika Jonsson's autobiography, which started yesterday, has been reported as costing the Mail and its sister Sunday paper £700,000 - a sum that staggered rivals on the Sun and the Mirror, although sources at the Mail say the figure is closer to £400,000. The deal was all the more surprising because the bidding was "blind": newspapers were not told about the contents of the book in advance. It had been heading to the Express, who had agreed to buy it, according to Mail sources, but when the deal was not completed the Mail were quick to take it up.

The Mail, more than ever, is determined to price its rivals out of the market - and there is growing evidence that publishers are bypassing the open market and going straight to Associated, which is even said to bid for books simply to take them off the market. The Mail's book deals are signed by literary editor Jane Mays, who uses a handful of readers to assist her. Their job is to read the books and report back with a short precis. These are then discussed by Mayes, editor Paul Dacre and his deputy Alistair Sinclair. They work out what it is worth to them, the tactics, and the money.

Peter Willis, associate editor and head of features at the Mirror, says: "It's as if they're working on different criteria from the rest of us. Most of the time we would buy books on the potential sales rise you could get out of them, but their brief seems to be to get as many books as possible at any cost. They are working on a different scale."

The Mail's list of catches has certainly been impressive, and has spanned the genres. Lord Archer, the former Coronation Street actor Amanda Barrie, singers Nicole and Natalie Appleton, and former Labour ministers Tony Benn and Mo Mowlam have all taken the Mail shilling. The size of the Associated chequebook appears to have transcended all political and social allegiances.

Brian MacArthur, in charge of serialisations at the Times and the Sunday Times, agrees that the Mail group's firepower is impressive. "The Mail has always had a massive wallet, and it hates to lose."

The Mail titles - like the other tabloids, and to a lesser extent the broadsheets - look for a revelation in their serialisation deals: a killer fact that will drive readers to the paper through a dramatic front-page story. But broadsheets would be just as likely to go for extracts from a prominent fiction writer on its literary merits - witness Martin Amis's deals with the Guardian. "Celebrities are a curse to deal with," says MacArthur. "They demand approval of every caption, every headline and every standfirst." But for newspapers like the Mail, they are crucial to driving sales. Publishers point out that the Mail is good for them, too. It helps shift books.

The Mail buys hundreds of books a year. As well as the blockbusters, there are the diet and health books for Femail; history books that will make a Saturday feature; or cookbooks for the recipe pages, some of which will only command a fee of a few hundred pounds.

But it is the blockbuster buy-ups that command the biggest attention, and they seem to be on the increase. Willis says: "There have been eight or 10 big books in the past few weeks, and all of them without exception have delivered on their promises."

Tabloid executives believe there has been a significant shift in the trend for celebrity autobiographies. Whereas once the genre was a means for an ageing star to record the experiences of a lifetime, it is now seen as an important tool in an aggressive marketing campaign. Nicole Appleton's claim in her book that record industry executives pressurised her into aborting Robbie Williams's child was a sensational revelation - and it was no coincidence that the serialisation deal (sold to the Mail, naturally) appeared at the same time as a new single.

Willis says: "TV tie-ins and celebrity autobiographies have been a massive growth area. Will Young has already got his autobiography out; and Geri Halliwell has updated the one that came out two years ago by adding a couple of chapters and selling the rights all over again."

Some deals are signed far in advance. The Mail, for example, has already bought the rights to Julie Andrews' autobiography, which has not even been written yet.

One prominent books buyer described the ideal autobiography serialisation as "Camilla - My Story". Willis goes one better: "I'd like to see the Queen's autobiography. What she really thought of all those people she met over 50 years, all those prime ministers. Now that would be a cracking read."