There will not be a significant surplus left over from running the Games but London 2012, which was quick off the mark to secure sponsors after being named as host in 2005, is in positive mood with 100 days to go to the start of the Games.

"We have always tried to push up revenues and keep costs down with every penny and try to bring them as closely balanced as possible," said Deighton.

"I am very, very confident we will hit the revenue target given the tickets we have left and the merchandise sales, we can be absolutely sure of that.

"But at this stage in the project there are always more strains on the cost side of the operation than on the revenue side."

Private sector

London 2012 must raise £2 billion from the private sector to stage the Games. London has now exceeded its sponsorship revenue target and is expected to raise more than £700 million.

Mr Deighton said that the necessary expenditure on the remaining preparations, including fitting out all the venues for the Games and constructing a number of temporary arenas, would swallow up most, if not all, of the income.

London 2012 has sold seven million Olympic and Paralympic tickets to the public and has another four million to go.

The remaining ticket sales alone should easily cover the £200 million gap to reach the revenue target, while income from sponsors has already exceeded expectations and merchandise sales should add to that.

More than £1 billion of sales is expected from the London 2012 merchandising programme, contributing more than £80 million to the staging of the Games.

By Games time an estimated 10,000 merchandise items will be on sale in the UK.

Test events

The bulk of the test events, which are trialling everything from the venues, field of play, communications procedures, security and staffing, have nearly been completed.

The Government and London 2012 organisers Locog have been keen to stress to both the public and the IOC that the £9.3 billion Olympic project is in good hands.

Trying to trigger public excitement and community involvement, through the torch relay and recruitment of 70,000 volunteers, plus regenerating London's deprived east end, are key parts of the run-up to the Games.

At the end last month's final inspection of Games preparations, International Olympic Committee president Jacques Rogge said he was confident that London 2012 "will be a great Games", adding: "We are a happy International Olympic Committee."

He had high-level talks with the Government and London 2012 executives about legacy, transport and security.