A mint condition paperback copy of Harry Potter and the Philosopher’s Stone was kept in an attic for nearly 30 years and is now set to fetch up to £10,000 at auction – after originally being sold for just £4.99A mint condition paperback copy of Harry Potter and the Philosopher’s Stone was kept in an attic for nearly 30 years and is now set to fetch up to £10,000 at auction – after originally being sold for just £4.99