A unique handwritten Harry Potter story, bought at a charity auction for £25,000, has been stolen in a burglary, amid fears thieves will dispose of it without realising its worth.

The 800-word prequel, written on a postcard by JK Rowling to raise money for charity, was taken along with jewellery from a safe in a house in Birmingham while its owner claims to have been away on a Bangkok business trip with Steven Seagal.

Rowling herself has issued a plea to Harry Potter fans not to buy the work, which is the only handwritten copy in existence.