People start believing they're important and Damien has started to believe he's important

Modern Painters editor

"And he still believes he can do it. That's what he tries to do."

Hirst also accuses Saatchi of arrogance, saying: "He tried to buy Midland Bank. And then he suddenly tried to control art."

Charles Saatchi was an early champion of Hirst and has bought pieces by many young British artists.

Hirst's attack on Saatchi, who bought one of the artist's sculptures, Hymn, for �1m in 2000, will surprise many who have observed the patron's buying policy - and feel that he has been too close to Hirst and other young artists.

Karen Wright, editor of Modern Painters, defends Saatchi from criticisms from both sides.

'Admirable'

"Saatchi doesn't buy indiscriminately - he has a very good eye," she told BBC News Online.

"He buys in mass, but he buys early and I think that's an admirable quality in a patron.

Saatchi: "Has a good eye"

"People start believing they're important and Damien has started to believe he's important.

"He is important, he has this iconic significance, but his criticisms of Saatchi are wrong."

In the book, Hirst also has sharp words for another champion of contemporary British art, Tate Modern director Nicholas Serota.

"I'm not Nick Serota's barrel-organ monkey," he is quoted as saying.

The book is also said to quote the artist extensively on his turbulent life and his experiences with drink and drugs.