Ian McEwan has praised the big-screen adaptation of his novel Atonement.

The movie, which stars Keira Knightley and James McAvoy, won Best Film at Sunday's BAFTA Awards after receiving 14 nominations.

The author admitted initial concerns about the film's budget and its ability to capture the essence of the novel, but insisted he was happy with the final result.

He said was moved by Saoirse Ronan's portrayal of troubled Briony Tallis, who changes the lives of those around her when she accuses her older sister's lover of a crime he did not commit.

The 13-year-old actress is nominated for a Best Supporting Actress Oscar for the role.

McEwan added that McAvoy and Knightley "worked marvellously together" and praised screenwriter Christopher Hampton's inclusion of particular details from the book.

He also highlighted director Joe Wright's "lush visual sense" and "real sense and eye for instinct, for the emotional heart".