A battered old Harry Potter book bought for 50p from a charity shop has sold for £15,500 in a hard-fought auction.

The first edition of Harry Potter and the Philosopher's Stone is one of just 500 copies from the first run in 1997.

Described as "charming" by the auction house, it is full of a child's scribbles and was initially expected to sell for about £3,000.

It was found among the dusty boxes of a Manchester charity shop and sold following a "colossal battle".

An anonymous collector in the US was the lucky bidder in the end.

"What a battle for the battered and bruised Potter," auctioneer Charles Hanson said.

"It deserves to be in a museum. Those doodles, penned by a child who loved the book and its characters, demonstrate the power of the Potter phenomenon in the late 1990s.

"It really is quite charming. I'm absolutely delighted for the seller and the buyer, who has purchased a piece of book history."

The seller, who also preferred to remain unnamed, said he was "astounded" at the result.

"I know it's a piece of modern history but the result was extraordinary," he said.

The JK Rowling novel was auctioned at Hansons in Staffordshire alongside a pristine copy of the same book, which sold for £69,000.

That copy, which was unread and had been stored in darkness for 25 years, was described by auctioneers as "good as new".

The seller, a retired paper merchant's director from West Sussex, said he was "very pleased".

"I've really looked after it," he said. "It's in the best condition it possibly can be - almost perfect I would say. It's never been read.

"A year after I bought it, with Harry Potter excitement growing at my daughter's school, she asked if she could read it. I said no, absolutely not."

The 68-year-old said he bought her another copy and kept the first edition "tucked it away in darkness" and away from "prying eyes".

It was snapped up by another US bidder and sold above its guide price of £40,000-£60,000.

The first Harry Potter book tells the story of the young wizard's days in Hogwarts School of Witchcraft and Wizardry and was followed by a further six books following his adventures.