The Queen has congratulated the UK's Beijing heroes, as London became the official Olympics city.
She said Team GB's efforts - its best Olympic medal performance for 100 years - would inspire London in four years.
The Beijing closing ceremony and the official Olympic handover was shown on 30 giant screens across the UK, while London staged a free concert.
Meanwhile, Prime Minister Gordon Brown says he wants to see a Great British football team at London 2012.
"The British public would find it strange if there was no British team," Mr Brown told BBC Olympic Breakfast.
As a nation we now look forward to holding the Olympic Games in London in 2012
There was no British football team in Beijing because the Scottish, Welsh and Northern Ireland football bodies feared it would affect their status within governing body Fifa.
The prime minister attended Sunday's closing ceremony in Beijing, which started at 1300 BST and included an eight-minute slot for London to give a flavour of the kind of Games it is planning.
The sequence featured footballer David Beckham, singer Leona Lewis, a red double-decker bus and an innovative musical sequence combining elements of the BBC Radio 4's shipping forecast, Jerusalem and Greensleeves.
London Mayor Boris Johnson received the Olympic flag and the Union flag was carried by cyclist Chris Hoy, who won three gold medals, a feat achieved only once before by a British athlete.
At the same time a handover party was being held outside Buckingham Palace with a concert featuring Will Young, James Morrison, McFly, The Feeling and Scouting for Girls.
An estimated 40,000 people flocked to The Mall and the party is set to go on until 1700 BST.
Team GB won 19 golds and a total of 47 medals, earning Great Britain fourth place in the medal table, far higher than the eighth place hoped for by the British Olympic Association.
Brown backs GB football team
But members of the public hoping to welcome members of the team when they arrive at Heathrow on Monday have been told to stay away.
A spokeswoman for British Airways said a joint decision by the police, the British Airports Authority and the airline was made to encourage people to stay away from the airport, because of health and safety fears.
The athletes would not use the main concourse and would not be visible to the public, she said.
Britain's Olympians will attend a Downing Street reception at some stage after their return to the UK, and a victory parade for the team will be held in London on 16 October.
The Queen said: "As the Olympic Games in Beijing draw to a close, I have been particularly impressed by the British and Commonwealth athletes who have taken part in this memorable competition and who have contributed so much to the spirit of these remarkable Games in the various disciplines.
"Like so many people around the world, I have followed their endeavours with great interest and admiration."
The Queen said she sent her "warmest congratulations" to all the participants and those who had supported them.
James DeGale with Britain's last gold medal, its 19th in total
She added: "As a nation we now look forward to holding the Olympic Games in London in 2012.
"The golden triumphs of the present British team can only serve as further inspiration to those who will be working hard over the next four years to make the London Games a shining example of Olympic success."
Mr Brown has said the honours system would recognise the success of Great Britain's Olympic team.
The Cabinet Office said the sports honours committee would meet in September before the New Year's honours list is announced at the end of December.
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