RACY literary hit Fifty Shades Of Grey has become the fastest paperback to hit one million sales – and smashed its own one-week sales record.

The erotic tale, the first in a trilogy by EL James, reached seven-figure sales in only 11 weeks. It hit the target 25 weeks faster than the previous record-holder, Dan Brown's The Da Vinci Code. And the book has shattered the seven-day sales record for an adult paperback which it set only last week – by selling almost twice as many copies.

Fifty Shades shifted 397,889 paperbacks in a week, bettering the 205,130 it established just a few days earlier. But both of James's follow-up titles also bettered that figure, according to the latest figures from Nielsen BookScan which compiles book industry data.

Fifty Shades Darker sold 245,801 while Fifty Shades Freed sold 212,832.

Mother-of-two James – whose real name is Erika Leonard – has already sold the film rights to Fifty Shades Of Grey, which began as an online tale.

Her books follow the erotic adventures of a young graduate and her submissive relationship with a handsome billionaire.