David Cameron has warned there must be "a big cultural change" towards sport in schools if Britain is to capitalise on the Olympic success of Team GB.

The Prime Minister called for a return to the "competitive ethos" in school sports and he hit out at teachers who were unwilling to play their part in coaching and mentoring young talent.

He said that while the Government is investing £1 billion in school sports over the next four years, more needed to be done if Britain was to enjoy continued sporting success in the future.

"Frankly, if the only problem was money, you'd solve this with money. The only problem isn't money," he said. "The problem has been too many schools not wanting to have competitive sport, some teachers not wanting to join in and play their part

"So if we want to have a great sporting legacy for our children - and I do - we have got to have an answer that brings the whole of society together to crack this, more competition, more competitiveness, more getting rid of the idea all must win prizes and you can't have competitive sports days.

"We need a big cultural change - a cultural change in favour of competitive sports. That's what I think really matters. And one of the answers there is making sure the sports clubs really deliver in terms of sports in our schools."

Mr Cameron said that while sport had been part of the national curriculum under the last Labour government, ministers had failed to ensure it was actively encouraged in schools.

"What the last government did that I think isn't right is if you just simply sit there in Whitehall and set a target but don't actually do anything to help schools meet it, you are not really solving the problem," he said. "By just saying 'Look, I want you to do this many hours a week' some schools think 'Right, as I've hit that minimum requirement I've ticked the box and I can give up.'"

Mr Cameron acknowledged that since the coalition came to power, 21 school playing fields have been approved for disposal - despite a promise in the coalition agreement that they would be protected.

He insisted that in each case it was because the schools concerned were being closed or merged, the land involved was marginal, or it was for reasons of improving sports access. "It was a mistake that playing fields were sold in the past. They are not being sold any more," he said.

The Press Association, photo by The Prime Minister's Office