Cowell's production company Syco makes the X Factor show

The deal assures a return for the talent show and means Cowell will appear on ITV until 2009.

He will also bring his number one US series America's Got Talent, which features former Daily Mirror editor Piers Morgan on the panel, to the UK.

"ITV gave me my first big break in TV five years ago for which I will be eternally grateful," said Cowell.

"It has been a fantastic relationship which continues to go from strength to strength."

ITV director of television Simon Shaps said: "I am absolutely delighted to be working with Simon, and his production company, on X Factor and a variety of exciting new formats over the coming years".

The network would not comment on the money paid to Cowell, but if the reported figure of �20m is correct it makes him the UK's highest-paid television personality, knocking Jonathan Ross into second place.

10.4 million viewers saw 21-year-old Leona Lewis crowned the winner of The X Factor on Saturday night.

Her prize was a �1m recording contract, and she will now release a version of the song A Moment Like This, which was first recorded by American Idol winner Kelly Clarkson.