“There’s a whole chunk of sport which has enormous value to society but isn’t talked about because it’s not sexy enough,” says Sir Keith Mills, the founder of the charity Sported, on a bracing December morning on one of London’s largest housing estates. “But you only have to look around to see what grassroots sports clubs can do for communities, especially in disadvantaged areas.”

It is 11 years since Mills set up Sported with £10m of his own money as part of his commitment to deliver on the legacy promises of London 2012. This month he will step down as chairman having seen the charity grow to more than 3,000 members, who all use sport to tackle issues such as homelessness, youth unemployment, knife crime and gangs. And in Burgess Sport, an association of local sports groups operating out of Burgess Park in Southwark, south-east London, Mills has a textbook example of how Sported can change lives.

He listens as Vernon Neve-Dunn, a volunteer coach, explains how Tre Whyte and Quillan Isidore – who both learned their skills at the Peckham BMX club in the park – are now part of British Cycling’s squad with ambitions of competing at the Olympics. “But there’s dozens of other kids off the local Aylesbury estate whose lives have been transformed by sport,” Neve-Dunn says. “Many of them are also developing leadership and organisational skills thanks to Sported’s help, which is something they can use in their everyday lives.

“Of course we’ve lost with some kids because they’ve drifted off and got into gangs and stuff,” he adds. “But we’ve won with a lot too. Kids such as Silas Paul-Johnson, a volunteer coach who is now with London Scottish and is part of Sported’s Young Leaders programme. And Romari Doswell, a big kid from Peckham with a stutter who is now at Swansea University doing sports science after we put him through training courses.”

Mills has heard countless such stories in the past decade. What is different with Sported, he stresses, is that it has a bottom-up approach and targets many of the poorest areas in the country. Its philosophy is to provide funding, training and other help to local clubs, and then let them get on with it.

“If you go around the country there are thousands of clubs like Burgess Sport who do an amazing job,” he says. “We understand that guys like Vernon know the kids and local communities better than any politician. Sadly these clubs are all struggling as local authorities have got less and less money. In fact many are living almost hand-to-mouth so what we try and do is help them in whatever way we can.”

Mills has a sporting CV that is longer and deeper than most. He was chief executive of the London 2012 Olympic bid campaign and deputy chairman of the committee that organised and ran the Games. He is also chairman of the Invictus Games – which he started with Prince Harry – and is a major player in sailing. For good measure he was on Tottenham’s board. Not bad for a housing estate lad from Essex who left school at 15 without any qualifications.

One of Sported’s early success stories was Lympstone amateur boxing club in Devon, run by Neil Parsons to benefit disadvantaged kids for nearly 50 years. “Many of them had been referred by either police or the local authority and he was an amazing mentor for them, not only in sport but helping them with their homework and job applications,” says Mills. “But the shop below had caught fire and burned out his boxing club. So we put some money in to boost the amount Lympstone got from Olympic legacy funding, and also put in a mentor to help Neil.

“The mentor found out he had a waiting list of between 50 and 100 kids all the time. So they built a club twice the size so he could look after 120 kids. We also helped Neil, who was in his late 60s, to recruit two firemen to come in as club leaders. It meant that when Neil retired as secretary the club was still able to thrive.”

But Mills admits it is not easy to raise the £2m a year needed to provide the financial and infrastructure help that is needed. “It’s a challenge,” he says. “We just hope that more funders will see the value of putting money into it.”

Yet he insists that Sported’s help is needed more than ever given the current economic climate. “I went up to Liverpool a few weeks ago to open a new sports club, which was set up by a guy who lived on the local council estate near the docks,” Mills says. “And I said to him: ‘Other than money, which is always a problem, what are your biggest challenges?’ And he replied: ‘Do you know what? Feeding the kids. I have to go to the food bank every morning so when the kids arrive I can give them something before they go off and go to school. That’s what we’re facing.’

“But our core message is these local community sports clubs have massive value to the community, and especially at a time where social cohesion is a challenge. Sported’s role is just to help them do what they do best.”