They have the badge. They have the football strip. They even have the WAGs. Louis Garvey, a coach at Manchester United, reckons that the only differences between the top-flight pros that play for England and his international squad are “fitness levels and the cost of the haircuts”. Well, that and the fact that they are homeless.

Garvey, the head coach of the Old Trafford club's Football in the Community programme, has been training England's Homeless World Cup team since its creation for the inaugural tournament in 2003. Today, he prowls the indoor turf of The Cliff, the United training ground in Salford, barking instructions to the men on the pitch. After six months of selection, this is the final team trial; 14 players are present, but only eight will make it to Melbourne for the competition in December. Each team consists of four players on the pitch and four substitutes, and can be all-male, all- female or mixed. “I choose players on ability and attitude,” says Garvey, “but we try not to let them get carrried away. We've had that in the past - the egos. This time we need to gel as a team.”

Mel Young, a former journalist and founder of Big Issue Scotland, came up with the idea of the Homeless World Cup over a drink with a few delegates while attending a conference in South Africa for publishers of street newspapers. When it still seemed like a good idea in the sober light of the following morning, he decided to give it a go.

Young set about organising the inaugural tournament in Graz, Austria, through word of mouth and his network of contacts. But to his amazement the small stands erected in the city centre overflowed with local support and big screens were had to be set up so that more people could watch. “Some of the people who came would have spat on homeless people on the streets a week earlier, but there they were watching the games and asking players for autographs,” he says.

Since then the tournament has come a long way: at the Homeless World Cup, organisers expect 100,000 spectators to cheer on 560 players from 56 nations. With daily highlights screened on a major Australian television network - and the final shown live - it's no surprise that the tournament has attracted corporate sponsorship from companies such as Nike, and that the England team has the support of the Football Association and British Airways.

To qualify to play, each footballer must be over 16 and have been homeless for a year. South American and African teams often include many players who have been living on the streets, but no rough sleepers - or women - have been chosen for England. The majority who make it into the team are young men in their twenties who live in hostels, or the sofas of friends. The rule is that you get to play for England only once.

“When you put on this shirt it means something. It means everything. You are England,” says Martin Hall, one of three contenders to be the team's goalkeeper. After a few hours of training, the 20-year-old is taking a break from the final try-out. Kicking back, he seems carefree but nothing could be farther from the truth. He grew up with four brothers and sisters in the West Midlands but left home as a teenager after falling out with his mother. “The younger kids got everything, and the older ones like me got nothing,” he says. Now he says he is calmer; he has a girlfriend, and plans to move from supported living into his own flat. To most people, Hall is a statistic; one of the 95,000 people classified as homeless last year in England. Today, though, he is a footballer.

In its short history the Homeless World Cup has had an abundance of plots worthy of Hollywood movies: former child soldiers, an Australian man who gave up his home and job to pursue a woman he met on the internet (it didn't work out) and, two years ago, a Scotland victory in the final.

Some countries use the opportunity of the Homeless World Cup as a social project, mixing up less talented players, older men - even women - who have a better chance of benefiting from the competition in the rest of their lives. But Young agrees with the England team selectors that in principle the competition is primarily about football. “If it became a worthy social project the players wouldn't want to take part. Ninety per cent of the players are young men, but they are the ones who play the most football - and they are the hardest group to reach.

“It is comparatively easy to find other activities for homeless young women to take part in, but young men are hard to shift.” Nevertheless, a separate Women's Homeless World Cup will start this year.

At The Cliff, the players hoping to be in the England squad freely admit their desire to become professional footballers. “I'm not ashamed to say football is my life,” says Richard Hawkins, a goalkeeper. His history includes drink, self-harm and a grandfather who was murdered by Dr Harold Shipman. After losing his job as a chef in Wales, he left home at 17 and moved to Manchester to live with his natural father. When things didn't work out, he found himself in a city hostel battling depression. Discovering football, he says, kept him sane.

But the day after I meet him, Hawkins is in anguish. He has found out that he has not been picked for the team to go to Melbourne. Martin Hall will be the keeper instead.

However skilful they are, in reality it is unlikely that any of the players trying for the England squad in Salford will become professionals - a fact that Garvey is trying to emphasise at an earlier stage of proceedings. “I am trying a different approach this year. We're not pretending that they are professionals, because they're not. What I say is that I treat them the same way I'd treat professionals and I expect that from them. I expect them to turn up on time and bring their own boots and strips, and do what they are told.”

Most of the men at the trials are already in their twenties, and some are in their thirties. Histories of drugs and alcohol are common, and not all are in peak physical condition. One is sick after a hard day's training. Almost all of them live on benefits.

In its history the competition has managed to place a couple of players at the non-league clubs Stafford Rangers and Sutton Coldfield, but, according to Young, its success derives from the astonishing figures that accompany the changes in the men's lives. “After the first tournament we found that three quarters of those who took part had turned their lives around,” says Young. “They'd either found jobs or left the hostels and got proper houses. They were back in society. I didn't believe it. I asked for the figures to be double-checked. But they were true. It is more impressive to me to see a man who I once walked past on the streets get a job than it is if someone started playing for Manchester United.”

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