Simon Cowell's unauthorised biography with "lurid" details about his personal life may be detrimental to his career, TV executives have warned.

The media mogul is at the helm of Britain's Got Talent and The X Factor in both the UK and America.

But with sordid details about his relationships leaking out from Tom Bower's book that doesn't show Simon in a good light, TV bosses are fearful it may harm his successful brand.

"This whole week has been like an ongoing car crash," a senior ITV source told Britain's Daily Mirror. "There is a great deal of consternation here."

"These are really rather lurid stories that don't reflect well on Simon.

"And they certainly don't help when we are producing family shows like BGT and X Factor. Quite the opposite.

"We can't quite fathom why he would co-operate with such a book. It's baffling. I'm sure he will explain to us in the fullness of time."

There are stories about Simon's alleged "bonks" with co-judge Dannii Minogue, him allegedly bullying contestants and tales of how he treats women like "toys."

"This book is not written by me," Simon wanted to make clear on his Twitter page. "It is unauthorised. The writer is Tom Bower."