The first book in the trilogy remains in the number one slot for the sixteenth week running and overall sales have overtaken even those of The Highway Code. The second and third books, Fifty Shades Darker and Fifty Shades Freed, continue to sell strongly, with UK sales of 3.6 million and 3.2 million respectively. Combined UK sales for the trilogy are in excess of 12 million copies.

Commenting on the new record, EL James said: “My main ambition when I signed the deal with Random House was to see my books in the shops. I simply had no idea they would be so successful and this is totally unexpected. The whole process has been both extraordinary and rewarding. I couldn’t be more pleased with the sales and would like to thank everyone involved.”

Susan Sandon, managing director of Cornerstone Publishing, said: “The Fifty Shades of Grey phenomenon is perhaps one of the most extraordinary experiences of my entire publishing career and I feel privileged to be part of it. The speed and sheer size of the sales is incredible and the roles played by so many people across the business simply breathtaking. Each and every department across editorial, art, finance, legal, publicity, marketing, production and home and international sales has risen to the creative and logistical challenges presented by the trilogy with energy, excitement and passion. I take my hat off to the brilliance and professionalism of all involved. And above all, it is so much fun.”