THE erotic Fifty Shades of Grey trilogy of novels aimed at the female market has failed to halt a slump in traditional book sales.

Spending on books fell by almost £74 million last year, the lowest level for nine years, despite new titles by best-selling authors such as Ian Rankin and JK Rowling. Some of the fall has been attributed to a rise in the sale of e-books.

EL James's "mummy porn" saga accounted for one in every 20 books bought in the UK last year, new figures have also revealed. Fifty Shades of Grey is Britain's fastest- selling book, notching up 5.3 million sales.