The London 2012 Games have come in more than £350 million under budget.
Government figures released show that is the saving from the overall budget of £9.3 billion.
But none of that money will be used for installing the retractable seats in the Olympic Stadium - said to be vital if it is to be a base for a football club, as well as athletics.
So, where does that money go and who will pay for the stadium's conversion?
Here's our Political Correspondent Simon Harris.