J.K. Rowling's latest Harry Potter opus has sold for £25,000 at a charity auction.

The 800 word story was written on an A5 card, and auctioned for English PEN and Dyslexia Action. "I had great fun writing the card and I'm absolutely delighted that it has raised £25,000 for two such worthy causes," Rowling said in a statement.

The card concludes with the words: "From the prequel I am not working on – but that was fun." The story can be read at www.waterstones.com