A FIRST EDITION copy of ‘Harry Potter and the Philosopher’s Stone’ – containing author J.K. Rowling’s notes and original illustrations – is to go on sale at a charity auction.

The personal annotations from the best-selling author included comments on the process of writing and a section from an early draft of the novel.

They also included a note on how the best-selling author came to create the game of Quidditch.

It “was invented in a small hotel in Manchester after a row with my then boyfriend. I had been pondering the things that hold a society together, cause it to congregate and signify its particular character, and I knew I needed a sport,” she wrote.

Rowling also drew illustrations in the book, including a sleeping baby Harry on a door step and an Albus Dumbledore Chocolate Frog card.

The copy will be sold tomorrow at Sotheby’s in London as part of an auction jointly organised with the writers’ association English PEN.

The group, a charity that promotes the freedom to read and write, asked 50 acclaimed authors to “scribble second thoughts, marginalia or drawings” on a first-edition copy of one of their books.

Other participating authors included Kazuo Ishiguro, Ian McEwan, Seamus Heaney, Lionel Shriver and Yann Martel.

Sotheby’s said the funds raised will benefit English PEN.