Dennis wakes from his ever-say-die funk to announce that he will run in a London marathon against Whit, even though getting up the steps into his flat can be a challenge for him, pale, pudgy and puffing away on an endless chain of cigarettes. This is when Run, Fat Boy, Run finds its footing.

It's a romantic comedy told from the male perspective, with Pegg's character dividing his down time between doing the good dad thing with their young son Jake (Matthew Fenton), and a plan to win his ex-girlfriend back.

As a director, Schwimmer - who actually directed numerous episodes of Friends - underlines the jokes and adds exclamation points, but a softer touch probably wouldn’t have helped. A US import written and directed by Americans (screenwriter Michael Ian Black and director Schwimmer), Run Fatboy Run comes off as somewhat artificially imposed on British sensibility, and a long jog away from being funny.