LONDON, May 12 (Xinhua) -- Police in Britain's Birmingham city issued a global appeal Friday after a rare Harry Potter prequel, handwritten on a postcard by the author J. K. Rowling, was stolen during a burglary at a house in the city.

The story, penned personally by Rowling over two sides of an A5 size postcard, was described by West Midlands Police as "extremely valuable".

Police said the handwritten postcard was purchased to raise money for charity. They are hoping the appeal goes far and wide among Harry Potter fans throughout the world.

Investigating Officer PC Paul Jauncey said: "The only people who will buy this unique piece are true Harry Potter fans. We are appealing to anyone who sees, or is offered this item for sale to contact police."

Containing 800 handwritten words, it was sold at a charity auction in 2008 for 25,000 pounds(32,200 U.S. dollars).

Media reports said Rowling's words outlined a story set three years before the birth of the world's most famous fictional wizard Harry Potter.

It features the schoolboy wizard's father James Potter, and godfather Sirius Black, when they were teenagers. They are confronted by two "muggle" policemen after a high-speed motorbike chase but manage to escape on their broomsticks.

The proceeds of the auction were donated at the time to English PEN, which promotes understanding through literature, and the charity Dyslexia Action.

The Potter document was stolen along with a quantity of jewellery from the property on Howard Road in Birmingham's Kings Heath district.

Although it is thought the burglary occurred sometime between April 13 and 24, police only released details Friday.