The copy, which was signed by author JK Rowling, was one of only 15 produced for a competition to mark the 15th anniversary of Harry Potter and the Philosopher's Stone.

It was awarded to entrant Chloe Esslemont, then aged 16, from Cumbria.

Auctioneers had described it as "particularly scarce" as there was no record of similar copies being sold.

Publisher Bloomsbury organised the competition in 2012 and asked fans of the series to write a colourful letter explaining why they loved it.

Entries could only be submitted through specially-designed post boxes at participating bookshops and libraries.

The overall winner received one of the leather-bound books and a holiday to The Wizarding World of Harry Potter at the Universal theme park in Florida.

Ms Esslemont, then 16, was one of the runners-up who also received a book. She said she had "kept the book wrapped up in the attic for years" but had decided to part with it as "the money would be useful now".

The book, which contained a dedication to her, was sold along with her original competition entry which was in the form of a folding document inspired by the series' magical Marauder's Map.

Hansons Auctioneers, in Staffordshire, said there had been "lots of interest".

Speaking earlier this month, the firm's book expert Jim Spencer gave a guide price of £5,000-£10,000.