Of all the animals to be immortalised by cartoons, there are few less fluffy and endearing than the pigeon. Valiant, a cheap but occasionally charming CGI cartoon, takes one such scrawny-toed birdbrain (voiced by Ewan McGregor) and turns him into a hero of World War II. It sounds like a pretty far-fetched idea - until you remember that the British military actually gave medals for bravery to carrier pigeons.

McGregor's Valiant is a young wood pigeon with a small wingspan but big dreams. Fired up by a Citizen Kane-style newsreel, he flies his rural nest to join the elite and glamorous Royal Homing Pigeon Service, who carry secret messages across the Channel for the armed forces. Along the way he picks up a flea-bitten London pigeon (Ricky Gervais), and falls for a cooing dove-nurse (Olivia Williams).

"AS BLAND AS BIRDSEED"

Younger children will probably enjoy Gervais' puffed-up Bugsy, an endless repository of fart, belch and armpit jokes. But for older viewers this is generally as bland as birdseed - not actively noisy and stupid like Shark Tale, just lacking in either thrills or sophistication. The animation is serviceable without being inspired, and labours in vain against the basic ugliness of pigeons; they don't take naturally to human expressions and thus the most engaging characters are a pair of French Resistance mice.

In its favour, Valiant has two or three good jokes, McGregor's vocals are chirpy enough to make up for the flat visuals, and the supporting cast make for a diverting game of spot-the-celebrity. It's also pleasingly short.