James, 52, is the fourth wealthiest author according to the newspaper, after her tales of a sadomasochistic love affair seduced millions of readers and spawned a Hollywood film, party games and a lingerie line.
She has toppled Jackie Collins as the queen of the ‘bonk-buster’, pushing Collins, who has a fortune of £65 million, into fifth place.
But Harry Potter author JK Rowling remains in the top spot with £580 million - more than the combined wealth of the six authors below her.
James, who lives with her husband and two sons in west London, could climb higher up the rich list in the future as the second and third films from her novels hit the big screen.
Despite only managing mixed reviews, the first film, which was directed by Sam Taylor-Johnson, was a box office hit and is the second highest grossing release of the year so far.
A 30-second teaser clip for the next instalment, Fifty Shades Darker, was released earlier this week, although the full film is not expected until February 2017.
Barbara Taylor Bradford, who has sold more than 30 million books worldwide, is the second richest author with £149 million, while Lord Archer is third with £140 million.
Businessmen-turned-presenters Lord Sugar and Dragons’ Den’s Peter Jones are the richest television stars with fortunes of £1.04 billion and £475 million respectively.
Mr Bean star Rowan Atkinson, 60, has £85 million - up £8 million from last year - while Ali G star Sacha Baron Cohen and his actress wife Isla Fisher are valued at £80 million.
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