Simon Cowell's relationship with ITV has become increasingly strained by their lack of "respect" for the X Factor boss, it has been claimed.

Author Tom Bower, whose revelations in a book about Cowell raised eyebrows this week, accused channel chiefs of being "ungrateful" for his contribution to the network.

ITV is also said to have had concerns about some of the stories which have come to light in the book Sweet Revenge, such as unflattering comments about X Factor judges and acts. It also told how Cowell had an affair with former X Factor judge Dannii Minogue.

Bower's book - serialised by The Sun - says ITV executives have called the media mogul "disruptive" and "interfering".

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The writer told the paper today (Friday): "ITV executives are shooting themselves in the foot by criticising Cowell. They are risking a self-destructive war by not respecting the man who has saved their channel from bad ratings when they have failed to create other original and attractive programmes."

"He is a perfectionist and they are certainly ungrateful," he added.

Cowell, who normally guards his private life fiercely despite having such a high public profile, was interviewed regularly for the preparation of the book. Bower also spoke to family and friends.

But Max Clifford, Cowell's publicist, has already spoken of how working on the book had been a "massive own goal". He said he had spent the best part of a decade keeping stories about his client's private life out of the public eye.

Cowell has worked with ITV since 2001 when he became a judge on talent show Pop Idol, and he has a multi-million pound deal with the network to produce his shows X Factor and Britain's Got Talent.