Run, Fat Boy, Run (12A)

In a crowded week for British films this underdog comedy might have got lost but for a performance and a script of amiable absurdity by Simon Pegg. He plays a perennial underachiever who once had a lovely girlfriend (Thandie Newton) he was going to marry. Then he panicked and bolted. "You left her at the altar, pregnant," his friend reminds him. "But that was ages ago!"

Five years later he wants to win her back from her smarmy American suitor (Hank Azaria), and, in defiance of his reputation as a quitter, he promises to run the London marathon – in three weeks' time. Ex-Friends star David Schwimmer directs competently enough, but it's Pegg's odd instinct for comic by-play that keeps us on its side.