The National Audit Office (NAO) said the £9.3bn budget announced in March was “sufficient to cover the estimated costs of the Games” as it stood, but identified a number of areas within the built environment where costs could rise.
 
Unfinished design specifications, unpredictable construction price inflation and the extent to which private contractors will bid to become suppliers for the project, posed the most uncertainty over cost.
 
Auditor general sir John Bourn urged the government to carry out “clear and quick decision-making on funding, effective commercial arrangements with suppliers, and finalisation of designs and legacy plans”.
 
Should the costs surpass £10bn, the bill would have more than quadrupled since the £2.375bn estimate of 2003.