London mayor Boris Johnson has hit out at Britain's "nannying, mollycoddled, politically correct culture" which holds back the development of potential sports stars of the future.

Much has been made of a perceived lack of home-grown talent at the top end of sports across the board, with Scotland's Andy Murray the only genuine British contender at Wimbledon this year.

Johnson - who beat Ken Livingstone in the recent elections to ensure he would be in office when the Olympics come to London in 2012 - feels youngsters are not being encouraged to spend enough time enjoying "competitive sport", with many parents concerned over allowing their children to attend out-of-school activities or even let them have the chance of a kickabout in a local park amid safety fears.

Johnson said: "We need to look at our nannying, mollycoddled, politically correct culture in my view, which stops kids from going out and playing competitive sport.

"I also think we need to look at the shear fatness of the regulations which control people who want to help kids play sport.

"We need to think about the climate of apprehension we engender around anybody who wants to get into the business of coaching kids."

However, the London mayor rejected suggestions Britain's youngsters were a generation of video-game junkies and couch potatoes compared to other nations whose talented sportsmen and women are able to claim the top prizes.

Johnson was speaking at County Hall in Westminster along with Australian Open tennis champion Novak Djokovic, ranked number three in the world, to help launch a new initiative by sportswear giants adidas which will see five new 'adidas 2012 zones' built in partnership with the Local Authorities and for free public use ahead of the London Games.

The mayor hopes schemes like this will help "liberate the fantastic natural talent" in the capital.

When asked why countries like Russia and Serbia could produce champions, and yet Britain could not, Johnson declared: "We can produce great athletes. I reject your hypothesis.

"Our ambition is to liberate the fantastic natural talent that there is in this city.

"The kids need to be encouraged - and they need to be given time and the facilities to do it.

"We are going to ring fence LDA [London Development Agency] money for sport, we are going to be driving through a big programme of protecting sporting facilities and I am going to look very dimly at efforts to concrete over playing fields in London.

"I am absolutely confident we have all the natural talent we have got to give anybody a good old drubbing."

Johnson added: "What adidas are doing is fantastic and it is great they are encouraging sport in the five host London Boroughs by investing in new facilities.

"What we are trying to do in the mayoral team is to leverage the Olympics to make them a way of generating more excitement about sport and make sure we encourage and preserve facilities across London."

Johnson, meanwhile, also pledged to keep the key issues of London 2012, such as cost, in check.

The mayor's office announced a report published by David Ross, the Olympic watchdog appointed by Johnson, which revealed that new economic and market conditions had put additional pressures on the venues' budget - which had risen by £106million.

The report highlighted "areas of risk" including the Olympic Village, the Olympic Park legacy and security.

Johnson told reporters at this afternoon's adidas 2012 zones initiative: "I think the Olympics is going to be fantastic for the country and for London.

"Anybody who has been to look at the site will testify they are making great progress, all the pylons are in for the stadium already.

"It is going to be great, but we are four years out and now is the time to have a really hard think about the problems which lie ahead.

"We have got to stop the costs going out of control, we have got to get the security right and that we know where we are going - not just in four years' time, but in 14, 24 years' time with the legacy.

"What are we going to turn these great investments into? How are they going to be for the benefit of future generations?

"There is real scope to do fantastic things."