Fifty Shades pips Harry Potter to become UK's best seller
'Fifty Shades of Grey' has surpassed 'Harry Potter and the Deathly Hallows' with sales of 5.3 million copies to become the best-selling book in Britain.
EL James's erotic novel may have been derided by critics for "appalling writing" and by Barbara Taylor Bradford for its "boring" sex scenes, but that has not stopped women snapping up the tale of a virginal heroine who falls for a bondage-loving billionaire.
Random House, the publisher, said the book is now more popular than 'The Highway Code'.
The 5.3 million figure comprises 3.8 million physical books and 1.5 million ebooks, the Telegraph reported.
In terms of printed books, 'Fifty Shades of Grey' has yet to catch up with 'Harry Potter and the Deathly Hallows,' which sold over 4 million copies in the UK.
Harry Potter figures were based on print sales alone, as the series was not available in digital format when they were first published.
James's follow-ups, 'Fifty Shades Darker' and 'Fifty Shades Freed,' have sold 3.6 million and 3.2 million copies respectively, taking the trilogy to combined UK sales of over 12 million, according to data supplied by Random House.
Global sales of the trilogy are said to be over 40 million - still a long way from the 450 million achieved by JK Rowling's Harry Potter series.
James has described the success of the books as "completely and utterly overwhelming".
The book remains number one in the UK best-seller chart for the 16th week running.