Olympics: Cost of Games £400m under budget, but grass-roots sport will not see a penny

The final bill for the London Olympics is expected to be more than £400m under budget, but the saving will not be spent either on helping pay for the Olympic Stadium's redevelopment or as a windfall for grass-roots sport.

The stadium's future is expected to be settled next month and West Ham United remain favourites to be granted a 99-year lease. The delay in deciding the preferred bidder surrounds the cost of transforming the £500m stadium. The original budget was £38m to help convert it from its current 80,000 capacity, but the conversion West Ham want would cost £160m and negotiations continue between the Premier League club and the London Legacy Development Corporation . In all, four bids are under consideration.

Hugh Robertson, the sports minister, yesterday suggested that none of the unspent budget – currently £377m – would be made available to pay for stadium costs or to help grass-roots sport, despite calls from the likes of the Sports and Recreation Alliance for extra funds so as to capitalise on the Olympic afterglow and help make a rise in participation a reality. Yesterday, Sebastian Coe attended a Cabinet meeting to stress the need not to let this opportunity slip.

The Government is already committed to spending £1bn over the next five years on improving facilities at grass-roots level.

The final cost of the London Games will not be known until the start of next year, but as it stands the overall cost is forecast at £8.921bn from a budget of £9.298bn. There is likely to be a further fall as more contingency funding is returned with remaining contracts being wound up and the Olympic Village being prepared for handover.

Discussions also continue between Locog and G4S over the amount the firm will pay following the security fiasco.

Mr Robertson described the current estimate as "prudent". He said: "The £377m figure is conservative because there are lumps of contingency that are still attached to the outstanding work. The central expectation has to be in line with the rest of the project that not all of that will be needed. It is entirely reasonable to expect that figure to rise."