A SET of signed first editions of the first four Harry Potter books has sold for £17,000 in Swindon.

The sum, which comes to £20,100 including commission, is less than the £25,000 estimated by Dominic Winter Book Auctions in its catalogue.

However, auctioneer Dominic Winter insists that the Harry Potter bubble shows no sign of bursting.

He said: "I suppose in a way that the figure is slightly less than we expected because it is a lot of money to be investing in four books.

"But I don't think that the bubble is bursting."

The books, written by JK Rowling, were won by a family in a national newspaper competition, and they decided to sell after enquiring how much it would cost to insure them.

The purchaser was Pontefract-based Cheviot Books, a specialist dealer which regularly stocks rare Harry Potter items.

The price of first editions of Harry Potter books decreases dramatically from the first volume onwards.

This is because whereas only a few hundred first editions of Harry Potter and the Philosopher's Stone were published, the initial print runs for later volumes ran well into the millions.

A signed first edition of the first volume might be expected to raise up to £15,000 at auction.

By contrast, a first edition of the fourth book, Harry Potter and the Goblet of Fire, might sell for only a couple of pounds, even if in superb condition.

Nevertheless, such a book would have several hundred pounds added to its value if it bore the author's signature, as Rowling is not a prolific signer.

Worldwide, the series has so far sold about 200 million copies in 55 languages.

Their success, along with that of the first two films in a projected series of seven, as well as extensive merchandising, have left Rowling with a personal fortune estimated to be as much as £280m.

Today, beginning at 11am, hundreds of works of art, ranging from oils to pen and ink studies, were due under the hammer at the auction house.

Dominic Winter Book Auctions can be contacted on (01793) 611340 or at www.

dominicwinter.co.uk.