It's 7.30am and the grass on Wandsworth Common in south London is covered with an exciting collection of sports equipment. Goalposts, hurdles, frisbees and balls lie at the ready, and around 100 children are starting to roll up, packed breakfasts in hand, for an hour of sports before they begin the school day.

This has been the scene every schoolday morning since April for pupils at Honeywell junior and infants' schools in Battersea, after an enterprising parent galvanised others into action to start a "Fit Kids" breakfast club. The initiative has been a huge hit with parents and children alike, and the club is due to restart for the autumn in a couple of weeks' time.

For headteacher Duncan Roberts, the suggestion from parent Patrick Munroe that the school should run pre-school sports sessions every weekday, rain or shine, was something of a gift horse. Like most headteachers, he has been grappling with the twin difficulties of how to action the government's extended day scheme and how to fill the extra hours. And second, again like headteachers across the land, he has been bombarded with information on the importance of making children fitter and giving them more time for physical activity.

The idea clearly married the two ambitions. Parents with children in the junior school and the neighbouring infants' school were invited to drop their children off at the common 90 minutes before school started. The children register and spend an hour playing netball, football, ultimate frisbee, athletics and circuit training. The instructors - the ratio is one to 15 - then accompany them on the five-minute walk to school once the session is over.

More focused children

The project's popularity last term surpassed all expectations. Most of the 148 pupils who originally signed up are still regular attenders, and many parents - and teachers - report that children are more settled in class, more focused and better behaved.

None of this comes as any surprise to Munroe, a fashion designer whose own children are 11 and 10. He feels so strongly about the importance of sports for youngsters that, seeing how little time was available for it in the state sector, he felt moved to plug the gap himself, setting up a company called Fit 4 Kidz. He has teamed up with Your Story, a charity that provides sports coaches, usually for disadvantaged communities, although the leafy environs of Wandsworth Common has its fair share of higher-income families.

"Doing early-morning sports is a recipe for success for kids. It's especially good for boys, because it burns off some energy and leaves them more able to concentrate in class, but it is great for girls too," says Munroe. "Most of the private schools I know start the day earlier, and often with sport - why shouldn't a state primary like Honeywell do it as well?"

Munroe had backing from local philanthropists for his scheme, although the funding dried up more quickly than he'd expected, and he's hoping to clinch a deal with another backer for this term. He currently charges parents just £1.50 a session.

One of the main problems, says Munroe, has been getting parents to believe their kids would be enthused enough to participate. "We got a lot of mums and dads who said, my kids will never get up early for this. But what I said was: you tell your kids they have to get up early, and they will. And the thing is that most of them have adjusted to the early mornings, and really enjoy the sports on offer here, and they're happy to get up for them.

"You offer them sports like you'd offer them a sweet shop: you make it look wonderful, you make it enormous fun, and of course they love it and want to be involved. And the fact is that if you get them hooked at five, you've got them hooked for life."

The project is in the process of being evaluated, but the early signs, says Roberts, are good. "The general feeling among staff is that it's been positive. But it's not universal - we have had some pupils who have seemed to be overtired. Overall, though, teachers have been pleased with children's performance."

The parents, clearly, are thrilled. "I wasn't sure whether Sam, who's 10, and Milly, seven, would be up for playing sport first thing every day," says Jo Lamiri. "But they've been desperate to come along; they really enjoy it. What's really good is the range of sport on offer. I think they've been more alert - it gets them raring to go as soon as they get into the classroom."

Katie Freeland, whose twin sons Tom and George are eight, says she has noticed a confidence boost since they started the sports sessions, and this is something Munroe says he has also been very aware of. The earlier starts were tough at first, says Freeland. "For the first two weeks, the boys found it really hard, but then they adjusted and now they're not as tired. I think it gives them more energy."

Amanda Sant says the effect on her son Monty, seven, has been marked. "I see real differences. He's a lot more focused - this has helped him to calm down in class. Concentration is the thing he's found difficult in the past, and I think boys in particular do need plenty of exercise. I'm completely sold on this idea, and you'll hear the same from most of the other parents around here."

So universal is the acclaim for the early-morning sports that it's hard to believe there could be a fly in the ointment. But funding, of course, is the big issue: it is a frustration to Munroe and Roberts that there is still uncertainty over whether they will be able to find funding to keep costs down this term. The scheme will go ahead regardless, but Munroe is aware that providing the sessions at real cost - about £6 a session - will exclude many families. "What I feel very strongly is that sport like this and a club like this should be available to all," he says.

His ambition is to expand the scheme to include other Wandsworth schools, and he has already approached several. "There's a lot of interest in it," he says. "I tell them that all I need is a greenfield site five or 10 minutes' walk from the school, and I can provide the coaches and the equipment."

Towards the end of last term, a team of chief executives was brought round to see the scheme in action, in the hope of encouraging corporate sponsorship. And the reaction from almost every quarter has been positive. "The best thing is how much the kids love it," says Munroe. "I feel like we're making sports as attractive as a sweet shop. They come along here and it's like: 'Wow. This looks exciting. I really want to do this!'."