A miniature Harry Potter book handwritten by the author JK Rowling is to be auctioned with a guide price of between £100,000 and £150,000.

The 31-page book was penned by the author in 2004 and features extracts of the welcome letter sent to the young wizard by Hogwarts that appears at the beginning of the first book in the series, Harry Potter And The Philosopher's Stone.

Pages of the book feature lines such as "students may also bring an owl or a cat or a toad" and "parents are reminded that first years are not allowed their own broomsticks".

The book is around four centimetres tall and six centimetres wide and is being auctioned online by Just Collecting.

Dan Wade, the company's head of collectables, said: "We've watched the market for the rarest Harry Potter books soar tenfold over the past decade or so, as childhood fans of the series have grown up to become serious collectors.

"I think every Harry Potter fan in the world would love to own this book, so we're expecting a lot of interest - and maybe even a couple of bids via Owl Post."

The auction ends on March 26.