Harry Potter: Rare book could fetch £500,000 at auction

The one-off edition is bound in brown morocco leather and adorned with semi-precious stones

A one-off edition of a Harry Potter spin-off book which was handwritten by JK Rowling is to be sold by its owner.

The bejewelled copy of The Tales of Beedle the Bard could fetch up to £500,000 when offered for sale at Sotheby's London next month.

Rowling originally gave it to Barry Cunningham, who accepted the first Harry Potter book for publication.

He now plans to sell it with her blessing and said he will donate some of the profits to her charity Lumos.

The Tales of Beedle the Bard was originally released in 2007 as a spin-off from the main Harry Potter series.

Cunningham's copy includes illustrations drawn by Rowling as well as a personal inscription.

The author wrote: "To Barry, the man who thought an overlong novel about a boy wizard in glasses might just sell… THANK YOU".

The book was handwritten and illustrated by JK Rowling

The book is bound in brown morocco leather and is adorned with semi-precious stones and a sterling silver mounted skull.

The editor, who now runs his own publishing house, played an instrumental role in launching Rowling's career as an international best-selling author.

The manuscript of the wizarding tales is one of only seven unique copies that exist.

Six were personally produced by Rowling for friends while a seventh was made specifically for sale at auction. It was sold for £1.95m in 2007.