Sir Richard Eyre is currently directing Mary Poppins in the West End

Sir Richard's other work commitments threatened to delay the movie by 18 months, a spokesman for production company Working Title Films said.

They "mutually agreed" to replace him with Pride and Prejudice director Joe Wright. No actors have yet been cast.

Atonement won the US National Book Critics Circle award in 2003.

'Best interests'

Sir Richard was director of London's Royal National Theatre from 1988 to 1997 and is currently directing the West End musical version of Mary Poppins.

He directed the movies Stage Beauty and 2001's Iris Murdoch biopic Iris, amongst others.

Our relationship with Sir Richard continues to be very good Working Title Films

"It was mutually decided that further delay was not in the best interests of the film because the book has been so popular," the Working Title Films spokesman said.

"Our relationship with Sir Richard continues to be very good and we are committed to working together in the future."

Sir Richard's spokesman did not comment.

Atonement tells of a 13-year-old girl growing up in the English countryside between the First and Second World Wars, who accuses a family friend of a crime.

The film's new director, Joe Wright, recently completed the latest movie adaptation of Pride and Prejudice, starring Keira Knightley and Matthew MacFadyen.