Watched by his wife Sophie, Prince Edward presented Kerrigan with the prize at the 10th British Film Festival in Dinard, northern France.

A panel of judges, led by French actress Jane Birkin and including Full Monty star Mark Addy, voted Human Traffic as their favourite film of the festival.

John Simm takes the lead role in the film

Released in June, the film follows the highs and lows of five friends on a frantic weekend of hedonistic excess in the Welsh capital. Its unflinching portrayal of drug use has led to comparisons with Trainspotting.

Grasping his award so tightly he broke it, 25-year-old Kerrigan said: "This is a very surreal moment for all of us. The fact that people turned up was really a plus."

But not everyone agreed with the judges' choice - part of the audience booed when the surprise decision was announced.

Other winners included Following, Christopher Nolan's film about a young stalker, and Fanny and Elvis, which follows a woman's search for a sperm donor, starring Kerry Fox and directed by Kay Mellor.

Other films in competition included Final Cut, set at a wake and starring Jude Law and Sadie Frost. Janice Beard 45WPM is the story of a woman who works in a typing pool who gets involved in romance and industrial espionage, featuring Patsy Kensit and Rhys Ifans.