The National Badminton Centre on the outskirts of Milton Keynes is an unremarkable modern building; only a huge sculpted wooden shuttlecock outside distinguishes it from all the other unremarkable modern buildings on the outskirts of Milton Keynes. Inside, striding the corridors, is a steady traffic of lithe young athletes, but also groups of florid businessmen. The centre generates extra revenue by opening its committee rooms for conference use, which is how a gaggle of suited sales executives comes to be standing on the balcony overlooking the main sports hall, idly watching a training session.
"He must be good, he's got his name on the back of his shirt," one of them observes. A yard or two away, unrecognised by the suits, Nathan Robertson suppresses a laugh. It is his lot to be one of the greatest players Britain has produced in a sport still associated with church halls, a sport in which excellence is still defined by a name on the back of a shirt. His lot, but would he also call it his misfortune? "That depends," he says with a grin, a few moments later. "It's not frustrating that I can walk down a street without being hassled. It is frustrating that I don't earn £100,000 a week."
The 30-year-old from Nottingham is tall, dark and devilishly handsome. It is safe to say that if he were a British tennis player of an equivalent standard, let alone a footballer, his face would gaze down on a hundred high streets, from billboards the size of badminton courts. Still, if anyone has raised the profile of badminton in recent years it is Robertson and his mixed-doubles partner Gail Emms, who became world champions in 2006 following their silver medal at the 2004 Olympic Games. Last week in Denmark they managed only a share of bronze as losing semi-finalists in the European Championships, despite being top seeds, but Robertson was carrying an ankle injury.
Fitness permitting, they feel sure that in Beijing they can go one better than their silver in Athens, where they led the Chinese pair Zhang Jun and Gao Ling, the defending Olympic champions, 11-8 in the deciding game of three, before finally succumbing 15-12.
Robertson and I are joined in one of the committee rooms by Emms. She is short, blonde, bubbly and was born to succeed in sport. Her mum, Jan, was the centre-forward for the England women's football team at the 1971 Mundial (a precursor to the World Cup) in Mexico. "She's got this amazing scrapbook. There's a picture of her playing in the Azteca stadium in front of 50,000, going round a defender and sticking it in the top corner. She still cycles, she jogs, she's amazing. She's probably fitter than me even now. If I didn't make a sports team at school she was, like, 'How dare you'. She got me into badminton."
Emms and Robertson became aware of each other when they were about 13 – she is the younger by less than two months – and started competing in the same junior tournaments. "At the Notts Under-16s Open I didn't have a partner," she recalls, "and my dad was, like, 'Go and ask Nathan Robertson'. So I did and he said 'OK', and we went and won the thing." It was a prosaic start to a partnership that would conquer the world.
Mixed doubles suits them both. "I'm the same level as the net," says Emms, "which is actually a really good height. Anything flat coming across, I can kill it. I'm the perfect height for net play."
They have been paired in every major tournament for the past seven years. "That's not bad even for a marriage," Emms says, laughing. But what about the seven-year-itch, I venture. "No, we're still quite happy together. But there are times when I know not to go near him."
"The rage," says Robertson.
"Yeah, when he's got the rage."
"I don't like losing at anything, especially badminton," he says. "Even in practice, if I'm losing I get really angry."
"Especially in practice," she says.
"Yeah. I don't get as angry in tournaments, because I can channel my anger towards my opponent. In training I have to release it in other ways," says Robertson.
"Release it? He just launches it. It can go anywhere." She shoots him a look, half-exasperated, half-affectionate. She is talking about his racket.
"Yeah, but Anthony has taken over for kicking it," he says.
Anthony is Anthony Clark who, with Donna Kellogg, did what Robertson and Emms were expected to do, and won the mixed-doubles title in last week's European Championships.
"Yeah, Anthony drop-kicks it, Jonny Wilkinson-style," Emms tells me. "Whereas I throw it," says Robertson. "It goes a bloody long way, too. And they break really easy."
How many has he broken, I ask, the image of genteel games of church-hall badminton expunged from my mind for ever. "I said hundreds in an interview with a Danish newspaper," he says, "and that's probably about right. In tournaments, maybe 20 or 30."
He still plays in the Danish league, which is the best in Europe, and well-supported, with 500 or so spectators at most matches, and proper TV coverage. Robertson is a regular on the Easyjet flight from Stansted to Copenhagen, but Emms, who used to play there with him, has given up. The travelling was getting her down. He now has a Danish partner instead. "But she's not as good as Gail, which can be quite frustrating. She's a bit rubbish sometimes."
They both assure me that top-level badminton is several times better than it was even four years go in Athens. "We're so much better now," says Emms, "but everyone else is too. The game has moved on an incredible amount. It's a lot faster, and you just have to look at the smash now compared with four years ago. It's up to 200mph or more.
Also, there are people from Asia and all over the world specialising in the mixed. Four years ago there were maybe six other pairs we considered dangerous. Now there are 15."
Robertson nods in agreement. "And everyone knows everyone else's game much better now," he says. "We've got our own video analysis on every pair in world, but they video us as well, and have specific tactics against us. But when it all comes together, we're still the best in the world. And we have four years' more experience since Athens. That was our first major final."
What a final it was, too, lasting 93 minutes and yielding the best-ever result for British badminton. Not that Emms and Robertson left the court with a sense of triumph. "We didn't feel like we won silver, we felt like we lost gold," he says.
Their dejection was compounded by what they felt was outrageous gamesmanship from their opponents. On the other hand, they've been known to pull the odd stroke themselves.
"People don't understand all the psychology that goes on," Emms tells me. "When we're facing each other across the net, my job is to make sure the other girl doesn't get one over on me. A lot of it's about momentum. When one pair is on a roll, the other is doing all it can to stop you. So you change the shuttle a lot, you wipe imaginary sweat from the court. All that sort of thing. It happens in tennis even more."
That said, they both felt that Zhang, in particular, overstepped the boundaries of acceptable gamesmanship in Athens. "Zhang's just an arse," says Emms, with feeling.
She intends to retire later this year, she adds. "The Olympics are my only goal now. We've won Commonweath, European, World ... now I just need to get that Olympic gold."
And if, heaven forbid, they fail? "I don't know. I think I'm ready for the next phase of my life. I'd love to play in London in 2012, but I'll be 35, and I don't know if can commit to it for another four years. You have to be totally dedicated, but there are other things I want to do, like maybe start a family with my boyfriend. I'd like to stay involved in the sport, but I need a new challenge. Maybe I'll be Nathan's next partner's therapist."
They both laugh. I ask them whether they involve themselves in each other's love lives. "Sometimes I don't want to know about Nathan's life," Emms says. "It's much more complicated than mine."
"I'm currently single," he explains, "but I've got a 10-year-old daughter, who lives with her mum in Milton Keynes."
Needless to say, like Jayne Torvill and Christopher Dean before them, they are always being asked whether they are an item themselves.
They acknowledge the validity of the comparison. "There are no other sports where you get a man and a woman together as a specialist team," Emms says. "In tennis they play singles as well. We've met Torvill and Dean, actually. They said 'Ooh, we hear you're the new us'."
If they emulate Torvill and Dean all the way to the top of the Olympic podium, badminton's image as a sociable way to stay fit and catch up on village gossip will doubtless be eradicated once and for all. "We're really happy when people say we've changed the perception of the sport," Emms says. "Somebody had to. It's the fastest racket sport there is, and anyone who sees it live will be amazed by the speed and agility, the physicality of it."
As for the sexing up of badminton, she is happy to leave that to Robertson, who has posed naked in Cosmopolitan. No, she says, she has no plans to do likewise in Zoo. Not even with strategically placed shuttlecocks? "Er, no."
Maybe that odd word shuttlecock, I suggest, has done badminton no favours over the years. "Yeah, but we just say shuttle," Robertson says. "I don't know where shuttlecock comes from. It's one of the things we should know. They should give a hand-out to players, with a list of interesting things to say when asked." More laughter, I think perhaps at my expense.
Anyway, it is time for them to go and meet the visiting shadow sports minister, such are the privileges of being badminton's first couple. But before they do I'd like to know, if it's not too rude to ask, how much they earn? What are the financial rewards for playing badminton as well as anyone in the world? "We're pretty well paid," says Robertson.
"We do all right," says Emms. "We've been able to make investments."
"There are maybe 30 full-time players," Robertson says, "but maybe only four could carry on if Sport England stopped their funding. And we'd struggle too if we had no travel expenses. It would be very difficult surviving on prize-money and sponsorship alone."
"And prizes are paid in dollars, which isn't great," Emms adds. "The biggest pay cheque we've ever had was $15,000 [£7,500]. That's pretty pathetic if you look at tennis. But there's huge potential in Asia. There are millionaires out there who adore the sport, and want to take it over. You might find 10 years from now that it's exploded in Asia and all the best players are out there."
And will she envy them, back in Bedfordshire raising her kids? Not if she has an Olympic gold medal, she won't.
Crown Court: Britain's badminton big hitters
Born: 23 July 1977, Hitchin
Five-times English mixed ladies champion. Six-times women's doubles champion at the national championships. Bronze medal in the women's doubles at 2002 & 2006 Commonwealth Games. Gold with the mixed team in 2002.
Born: 30 May 1977, Nottingham
Six-times men's doubles champion at national championships. One mixed doubles title without Emms. Six medals at Commonwealth Games.
MEDALS AS DUO
2004 European Championships.
2006 Commonwealth Games.
2006 World Championships.
2004 Olympic Games.
2002, 2003, 2005 Mixed doubles champions at the national championships.
Currently ranked sixth in the BWF world rankings.