IT could have been a scene from a very British film. There's a knock on the door of a house in the heart of the industrial north. It's the man to repair the arm of the settee. As he works away under the watchful eye of a little girl, he spots a large photograph on the wall, a youth resplendent in ballet costume in the perfect pose of a dancer.

The repair man asks who the ballet dancer is and is more than a little taken aback when she says it's her brother Mark. He'd seen the house, he'd met the family, he'd made a judgement.

"The man had seen me and my tattoos and said to her 'looking at your dad you wouldn't think he would let him do it'," says John Richardson, the father of a real-life Billy Elliot.

"I know I look a bit rough with my tattoos, but I'm his biggest fan. Me and his mother love him and are proud of what he has done. It just shows you should never judge a book by its cover."

But that's what people do more often than not and when Mark Richardson decided he wanted to dance at the ripe old age of six, it wasn't a fact he made public.

Now a full-time professional with a major part in one of the best known musicals ever, Cats, Mark's thoughts of his struggle to be a dancer have resurfaced again with the launch last night of the North-East blockbuster Billy Elliot. The parallels are uncanny as are the coincidences - Mark taught the film's young star Jamie Bell to dance.

The film Billy Elliot is about a boy born to dance but having to do it in secret against the backdrop of the 1980's miners' strike and in a culture dominated by Northern machismo.

"When Mark got into Cats it was unbelievable," says John, of Normanby, near Middlesbrough. "We went to see him in it and it was fantastic. At the end he told his mother he loved her and she burst into tears."

His interest in dancing started young and was natural. No role models, no hero worshipping and no one else in the family, apart from his mother Carol who had once won a medal for dancing when she was the same age, but had not taken it any further. His older sisters Nicola, 27, and Tracey, 30, "have two left feet", according to John. And until health problems beset them both, Carol, 50, was a bus conductress and John, 55, a builder's labourer, so nothing artistic there.

"He used to play with a couple of girls and they used to take him down to the local dance school. He then told me he would like to dance and I thought he meant the disco. So I took him to the disco at Eston and he said not that kind of dancing, ballet or tap," explains John.

"So we took him to the dance school and he watched a few times then the teacher got him to join in. I said it was up to him. It was his life and he should do whatever he wants. Now I am his biggest supporter. I used to take him all over the region and it was absolutely fantastic, he used to win all the competitions. I used to be dead proud. I don't think he'll ever do anything else, he is just so dedicated."

John can barely wait to see Billy Elliot.

Scene two of the extraordinary story shifts 250 miles to London. And now Mark prowls like a cat, suddenly stretching, leaping, muscles taut, body toned, sweating, breathing hard, moving with the grace of the animal he tries to mimic, with half a dozen other dancers, staring intently at themselves reflected in a mirrored wall. Baseball cap, white vest, fur spats on his ballet shoes, he trains, practises for the evening performance.

Monday to Saturday, eight shows a week, he graces the stage of the New London Theatre as Carbuckty the kitten, one of the more demanding roles in Andrew Lloyd Webber's highly-successful production of Cats. Who is laughing now, certainly none of his former schoolmates at Gillbrook Comprehensive School, in Normanby, who used to rib him about his dancing. Now, as one of the most talented dancers in the country, he commands respect, particularly as he also understudies for Mistoffolees, one of the main dance parts in the spectacular.

Physically draining, it remains his dream job and something he has returned to after six months away from a show he first joined two years ago. "I've never wanted to do anything else but dance, certainly nothing mundane," he says while taking five at the Diamond Dance Studio, Shoreditch, in London.

"I always wanted to be in Cats, it's just something that always appealed. Cats has got to be the hardest routine physically, singing and dancing at the same time, but you get through it." It's this kind of determination which has got Mark from the industrial gloom of Teesside to the bright lights of the West End, overcoming the cultural differences of his working class background, the derision of peers and the fickleness of showbiz along the way.

It's the stuff of movies, particularly the story now being featured in Billy Elliot. He doesn't understand himself what sparked his interest in dance, particularly so young. "Even at six I cut myself off. I hated school and just wanted to dance. I didn't have a circle of friends I went out with. My life was just school, practising and going to dance class."

In a region dominated by the culture of the Northern macho male, he didn't advertise the fact that he danced. But the school kids soon found out. "It wasn't too bad. You got the ribbing but they soon got bored. You got the names but they soon forgot about you and you just became that lad that dances. People are never going to understand, especially up North, they can't possibly understand because it's all they know. It's all they have ever been told and they pass that on to their children. And they don't get the chance to find out." There are no hard feelings - but he wouldn't choose to live in Teesside again.

From instructor Lynne Cook, he joined the Maloney Dance School in Middlesbrough where he met and helped teach Billy Elliot himself, Jamie Bell. In fact he lent him his first pair of shoes and can't remember getting them back. "I taught him for a while; the teachers asked me to show him a few steps. He was very good at tap, but at that young age, about eight I think he was, it's hard to tell how he would turn out.

"It's really good that he got this part and I hope he keeps it going. You are always surprised and pleased when someone you know does well." Like his father, Mark is looking forward to seeing the film to see whether fiction mirrors fact, but he admits it does sound similar.

At 16 he left the North-East to train at a dance college, the Laine Theatre Arts. Three years there saw him qualify as an associate in ballet, allowing him to teach in future. He secured a place in the Blackpool 1970s musical Oh What A Night and worked at trade fairs in Germany.

At 22 his thoughts are already turning to the future. Like most athletes a dancing career is limited, cut short by the physical demands. "I have got some friends who are 30 and still dancing. But even now I'm thinking about what I can do with the skills and knowledge I have got," he says.

Overcoming Northern bigotry hasn't necessarily been the biggest challenge. "I would never tell anyone to go into this business. People think it's fun but it isn't. You get far fewer jobs than you go for.

"That said, if you want to do something badly enough you will keep going. You have to set yourself little goals and aim towards them. Most of mine I have achieved. But what is important is keeping the right attitude; don't ever do what you don't want to do."