A book linked to the BBC2 series What Not To Wear and written by fashion gurus Trinny Woodall and Susannah Constantine is emerging as one of the most profitable the publishing sector has seen for years.

What Not To Wear is one of the biggest Christmas sellers, banking a huge profit for publisher Orion.

The group, which is owned by Hachette, is rumoured to have paid an advance of less than £10,000 for a title that sold about 250,000 copies before the biggest book selling period of the year had even started. The BBC will also share in the windfall due to a royalties agreement.

Publisher Michael Dover, of Orion imprint Weidenfeld & Nicolson Illustrated, said the book was now the WH Smith's second-biggest selling item, beaten only by a 2-for-1 offer on blank video tapes.

Priced at £12.99, it is outselling other celebrity books and TV tie-ins, including Jamie Oliver and Nigella Lawson.

Aimed at the sartorially challenged, What Not To Wear is based on the TV series which habitually humiliates unsuspecting members of the public by offering them makeover tips.

The success of the book has surprised the publishing industry, given that the advance paid was a fraction of the sums needed to secure other celebrity books in recent years. "What Trinny and Susannah do is proving quite irresistible for millions of people," said Mr Dover.

Orion is thought to have been able to buy the book for a small sum because of low sales of Woodall and Constantine's first effort, Ready2Dress.

The title, published in February 2000, was linked to their now defunct website. However, a new format has proved far more popular. Orion claims to have 670,000 copies of the book distributed to booksellers after more than a dozen print runs. A new series of What Not To Wear has been commissioned for the autumn, while a live tour is planned for the summer.