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The third installment EL James' bestselling Fifty Shades series has been replaced on the best-selling chart by Alice Peterson's Monday to Friday Man.
The steamy Fifty Shades trilogy has become a phenomenon: the first book in the series, Fifty Shades of Grey, is now the UK's biggest-selling book of all time.
But with Peterson's fourth novel, she has managed to dislodge James' hit novel from the number one spot - something the author puts down to the realism of her novel.
'The dog-walking fraternity love it,' explained . 'They recognise the tree and the dogs. There's a lovely man I walk with and I borrowed his fashion sense.
'I was very honest with them as I was writing it.'
Meanwhile, speculation is still rife as to who will star in the big screen adaptation of Fifty Shades of Grey.
Stars such as Ryan Gosling, Emma Watson and Robert Pattinson all tipped to play Anastasia Steele or Christian Grey.