Hills believe there is every chance the the final official cost of the 2012 Olympics will top £20bn.

With the government currently insisting that the cost will be £9.35bn, Hills have opened a book on what will be the final official cost of the London Olympics as confirmed by the government, and they offer 16/1 that it will come in at under £10bn.

Hills offer 4/6 that the final cost will be between £10bn and £20bn, and quote 11/10 that it will soar to over £20bn.

'With several years still to go it seems highly unlikely that the government will be able to keep costs down to under £10bn and in all likelihood the costs will continue to rise significantly.We think there is every chance that it will eventually more than double' said Hill's spokesman Graham Sharpe.