London officially entered the race to stage the 2012 Olympics today with letters from Prime Minister Tony Blair, the British Olympic Association (BOA) and London Mayor Ken Livingstone sent to the International Olympic Committee nominating the capital as an "applicant city."
Barbara Cassani, who heads the bid, said: "This is a really important day that marks the first official step in our bid that will finish with winning the Games in 2005."
In his letter to the IOC president Jacques Rogge, Mr Blair restated the Government's "wholehearted backing" for the bid.
He said: "We recognise the Olympic Games as the world's greatest sporting occasion. To participate in the Games represents the highest honour for our elite athletes.
"The British Government also wants to use this unique festival of sport as a catalyst to promote sports participation and physical activity in all communities throughout the celebration through the fundamental principles of the Olympic movement of respect, friendship and fair play.
All of London's assets will be used to ensure a "safe and vibrant" event, he promised. Similar sentiments were expressed by the BOA and Mr Livingstone.
The BOA said: "If London is ultimately entrusted with the honour of staging the world's greatest sporting competition, we can confirm that the organisation will be approached in a thorough, diligent and methodical manner.
Mr Livingstone said London was waiting with "open arms" to welcome the Olympic family. The Games are "more than just a sporting event" and would be a "real catalyst for much-needed revitalisation."
Technical details of the bid have to be put together and submitted to the IOC in January. If those are accepted, London will change status from an "applicant city" to a "candidate city" next spring with a further year to lobby and campaign ahead of the IOC vote in Singapore in July 2005.
The field is so strong the IOC may not be able to reduce the number of candidates before July 2005, Mr Rogge revealed in a visit to London last week.
If that happens, the final vote will be the biggest ever and the presentations to the IOC are likely to run over two days rather than the usual eight hours.
The IOC usually draws up a smaller shortlist of candidates who are visited by a special evaluation commission in the months before the vote. Rio de Janeiro, Paris, Madrid, New York, Leipzig, Moscow and Havana are among the rival bidders.