The hero of the latest British war movie is a pigeon called Valiant. A flight of fancy? No, it's based on real life

The farthest Daniella had ventured from home was a 28-mile trip down the M6 in the back of a white Vauxhall Astra van, so no one could be sure how she might respond when she was plonked in a field near Cherbourg and left to find her own way home. She made it, of course, extending her white wing tips to make the 300-mile trip to a loft at Audenshaw, north Manchester, in five hours with the rain and the wind on her nose - a performance that had some hard-bitten old pigeon men tipping their caps. It's not too often that a 12-week-old pigeon hen from the North pinches a national championship from under the beaks of the southern cocks.

The farthest Daniella had ventured from home was a 28-mile trip down the M6 in the back of a white Vauxhall Astra van, so no one could be sure how she might respond when she was plonked in a field near Cherbourg and left to find her own way home. She made it, of course, extending her white wing tips to make the 300-mile trip to a loft at Audenshaw, north Manchester, in five hours with the rain and the wind on her nose - a performance that had some hard-bitten old pigeon men tipping their caps. It's not too often that a 12-week-old pigeon hen from the North pinches a national championship from under the beaks of the southern cocks.

It also left the bird's owner, Gerry Clements, with the thought that has preoccupied him many a time in the 55 years he has been breeding pigeons. "All that bird's known is her training run home from Stoke," he says. "She's never seen the sea but suddenly she's flying over water - more and more and more of it. Some birds will turn back but the best ones, like her, they just keep going. Where does she get the courage from?"

There's no room for philosophising like that in the pages of British Homing World - the pigeon fanciers' bible, where Daniella's win made her front-page news last year. But the bravest of the brave will finally get their dues this week in the £20m Ealing Studios film Valiant, which is already being touted as a successor to the Oscar-winning Shrek, one of Hollywood's biggest animation films.

Inspired by the role played by racing pigeons during the Second World War, the film, which will be released on Friday, is about plucky young Valiant, a wood pigeon who decides to serve his country in the only way he knows how. Accompanied by a rather less motivated young friend, Bugsy, he dons goggles and a bomber jacket and prepares to brave Von Talon, a sinister falcon with a Germanic rasp.

The film's voices include Ewan McGregor, who plays Valiant, and Ricky Gervais as Bugsy, as well as John Cleese, John Hurt and Hugh Laurie. It also provides a directorial debut for Gary Chapman, a 44-year-old Mancunian brought in as a designer, drawing and sculpting maquettes of the characters. He was offered the directing job because his ideas for Valiant were so extraordinary.

But the most improbable name on the credit list is Gerry Francis - the former England football captain, ex-manager of Tottenham Hotspur and a dedicated pigeon fancier who was drafted in to ensure Valiant was historically accurate and the illustrations were anatomically correct.

Like Gerry Clements, Mr Francis is passionate about the birds of the RAF's Homing Pigeon Service, who were carted into battle in wicker baskets on infantrymen's backs. Amid radio silence they were set free to fly across the Channel with vital information tucked into steel phials tied to their legs, dodging snipers and hawks deployed by the German falcon brigades.

One of Mr Francis's favourite pigeon stories involves Winkie, who was travelling in a Beaufort bomber forced down in the North Sea. Despite being heavily oiled, she escaped from her container and flew 129 miles to Scotland, leaving her crew behind in a dinghy. The crew were rescued and later held a dinner for Winkie, who basked in her cage as she was toasted by the officers.

Mr Clements also talks of the cock pigeon Gustav, the finest of the lot for many fanciers. His name might sound suspiciously foreign, but he was as English as they come. Released from a ship close to the coast of Normandy as the D-Day landings began, he faced a headwind of 30mph and the sun, which he used to navigate with, was hidden behind dense cloud. Yet he still managed the 150-mile trip to a pigeon loft in Thorney Island, near Portsmouth, after a flight lasting five hours and 16 minutes.

His handler, Sgt Harry Halsey, took the message strapped to Gustav's leg that read: "We are just 20 miles or so off the beaches. First assault troops landed 0750. Signal says no interference from enemy gunfire on beach ... Steaming steadily in formation. Lightnings, Typhoons, Fortresses crossing since 0545. No enemy aircraft seen."

Gustav was one of 32 racing pigeons awarded the Dickin Medal, the animal equivalent of the Victoria Cross, of which only 60 have been awarded across the entire animal kingdom. Although his war-hero status did not guarantee him a rosy retirement, it should be said. He met a sorry end when someone mucking out his loft stepped on him by mistake.

During the Napoleonic Wars, Belgian and Dutch newspapers also relied heavily on birds to receive reports from the front. News of Napoleon's defeat at the Battle of Waterloo arrived in England by pigeon.

Pigeons' feats of avian heroism during the First World War are commemorated at a memorial in Lille, northern France, that recalls the more than 20,000 military pigeons killed during the conflict. However, during the war, German forces took possession of thousands of birds from Belgium alone.

But the Second World War was the pigeons' finest hour. Many nations deployed them, including the United States, which had more than 3,000 soldiers and 150 officers in the United States Pigeon Service to take care of 54,000 military pigeons.

Few could match the British, though. The birds have a place in the same pantheon of heroes as Churchill and General Montgomery and many are listed in the honourable roll-call of Dickin medal winners, named after Maria Dickin, founder of the People's Dispensary for Sick Animals. There was Cologne, who made it home, severely injured, from a British aircraft that ditched in the German city in 1943; Commando, who made three trips from occupied France; Princess, who flew 500 miles from Alexandria, Egypt, to allied forces; and GI Joe, America's finest, who raced home to Air Support Command at 60 miles an hour, just in time to reveal that a heavily fortified German position had been taken by the Allies and should not be bombed. One hundred lives were saved.

And what thanks did they get? So grateful was the Ministry of Defence that after the war it considered establishing a squad of germ warfare suicide pigeons to carry biological agents being developed at its chemical and biological research station at Porton Down in Wiltshire into the Soviet Union, in the event of war.

Valiant creates the uplifting impression that courage alone drove these humble creatures to glory. But another explanation of the flights they made - employing the sun, the earth's magnetic field and their rarefied sense of smell to guide them - has more to do with nurture: the prosaic, breeder's process of pairing those males and females that have the most acute desire to get home fast.

If Mr Clements had to send one of his 140 birds into battle it would be his retired racer Bouncer, or GB97N27828, as the racing world knew him in his prime, a blue pied pigeon with flecks of iridescent purple in his feathers who could never get back to Audenshaw fast enough in his five-year racing career, which ended in 2002.

He was sired by one of Belgium's finest cocks and, Mr Clements says, was destined to be one of the best because "the apple never falls far from the tree". The bird, like his war-time predecessors, also underwent gentle encouragement in what the pigeon world knows as the widowhood system. This allows the male a five-minute unconsummated liaison with the female on the day before a race. "By the time of the race, his hunger to nest - and do what males are supposed to do - means he's raring to get back," says Mr Clements. "Let's just say you wouldn't catch him stopping off at the pub on the way home from work."

There are other ways of encouraging a pigeon to get home quickly. When Daniella won the national, she was returning to a seven-day-old chick she had been encouraged to foster before competing. Or there is the more chaotic Spanish way, in which fanciers set off a hen that the cocks are allowed to dash after. Speed isn't everything: the winning Spanish cock must reach the hen first, then persuade her to venture home with him.

Spain also has a habit of turning the event into a circus. The pigeons are fed food dye that turns their feathers every colour of the rainbow - quite a spectacle as they leave en masse. But above all, the charm test brings out the harmonious, gregarious, companionable qualities in racing pigeons that are often overlooked in the stories of normal dour breeds that no one wants to see in Trafalgar Square.

Mr Clements - who hopes Ewan McGregor and co will finally add such qualities to our perception of a much-mocked bird - hasn't had a serious pigeon fight in his lofts for six years - only the occasional wrestle which accompanies one bird trying to annex another's box. After sleeping on their feet for as few as five hours a night, his birds will perch side by side from before dawn, hardly ever squatting. The training regime is the same as it would have been for the war birds: a single hour's exercise at 7am and 7pm, occasional 30-mile training jaunts and a strict diet of maize, peas, wheat and sunflower hearts.

Rumours of these birds' intelligence can be overstated. When BBC television crews pitched up a few years ago to investigate the (ridiculous) story that pigeons used the motorway network to navigate their way home, one of Mr Clements' birds was placed on a road atlas to see if it followed the blue lines. Predictably, it failed the test.

But their "brains, stamina and speed" makes them formidable, Mr Clements concludes, as he demonstrates the fuselage of a male bird, which made it 450 miles home with a broken keel bone and a foot that remains badly damaged to this day.

"There were cases in the war where they brought messages home after their chests had been ripped out and once they have delivered them they just dropped dead," he says. "It's because of those qualities we like to call them the athletes of the skies."