Simon Pegg’s latest comedy Run Fat Boy Run has raced to the top of the UK box office, taking more than £2 million in its opening weekend.

The film is the directorial debut of David Schwimmer and tells the story of a security guard (Pegg) who decides to run a marathon to impress a former girlfriend, played by Thandie Newton.

The adaptation of Ian McEwan’s novel Atonement, which has received rave reviews since it premièred at the Venice Film Festival, went straight into second place in its opening weekend.

Starring Keira Knightley and James McAvoy, the film took £1.6 million.

Matt Damon’s CIA thriller The Bourne Ultimatum is hanging on in third place after storming the box office on its release in mid August.