Inspectors from the International Olympic Committee arrive in London this week to examine the Capital's bid for the 2012 games.

Downing Street will stage a reception on Friday and the assessors will go on to dinner with the Queen in Buckingham Palace.

But bid officials have been asked to explain comments made in Australia by Cherie Blair, an ambassador for London.

The prime minister's wife may have breached IOC regulations by joking: "We are going to win the bid - what does Paris know about culture?"

Lord Coe, the chairman of London's bid, said yesterday that the race is too close to call.

He told BBC Radio Five Live. "People whose judgment I really value in this, and they tend to be IOC members but also people who watch this closely on a day-to-day basis, think we have narrowed the gap quite dramatically, but it is too close to call."

Meanwhile London mayor Ken Livingstone is set to announce tomorrow that an Olympic standard velodrome will be built regardless of whether the bid is successful.