In his book Down and Dirty Pictures, author Peter Biskind accuses Redford of having broken and failed to follow through on commitments.

He said Redford had been for keeping people waiting, and concluded that the festival was a failure.

Redford said the US festival’s success over 20 years spoke for itself.

Goal

Actor Redford founded the independent film festival 20 years ago, and last year it 38,000 film makers and investors to Park City, Utah.

This year’s Sundance opened on 15 January and will show 255 films including new movie The Clearing.

Biskind wrote: “Judged by one of its original, loftier goals, an institute to help outsiders, Sundance has failed.”

Asked about the book on Monday, Redford said: “You’re only human. You have to be disappointed, but you also know that there’s an impotence to your position.

“There’s nothing you can do about it. So you just live with it and move on.”

He added: “I’m pretty well okay with the fact that I think Sundance is not going to be stopped by that kind of stuff.”