The surprise sleeper hit of the summer in the US has been a French documentary, March of the Penguins (above), which charts the progress of Emperor penguins on their annual journey - in single file - to their breeding ground deep inside Antarctica.

Initially released at just four US cinemas, the movie has built such momentum that it is now playing on over 2,000 screens and had taken more than $48 million (€39 million) at the US box office by last Sunday night.

Not only does the film now rank comfortably ahead of far more expensive recent Hollywood studio productions - The Island, Stealth, Bad News Bears, Dark Water, Hostage, The Honeymooners, Miss Congeniality 2, The Great Raid, Lords of Dogtown - it has surpassed Bowling For Columbine to rank as the most successful documentary released in the US apart from Fahrenheit 9/11. Directed by Luc Jacquet, March of the Penguins was acquired by Warner Independent Pictures, which re-edited it for the US and added an English-language narration by Morgan Freeman. It opens here at Christmas.