The UK capital now holds the baton as official Olympic city, passed on by Beijing on Sunday following 16 days of athletic competition considered among the greatest Games ever.
London 2012 will not try to match the scale of Beijing, organisers admit
The run-up to the 2008 Olympics had been overshadowed by protests over China's human rights record and fears over security and pollution.
But the Games will be remembered for the right reasons - extraordinary feats of sporting achievement such as swimmer Michael Phelps's eight gold medals and Jamaican sprinter Usain Bolt's hat-tricks of world records and golds.
And as the action has captivated a worldwide audience of billions, Britons in their millions have been delighted, and astonished, by the country's best performance for a century.
A statement by the Queen said: "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."
London mayor Boris Johnson, who received the Olympic flag in Sunday's closing ceremony, said Beijing had hosted an "absolutely fantastic Games" - and predicted London 2012 would be "just as fantastic".
But a survey conducted some days into the Beijing Games suggested Britons were massively dubious about 2012, with just 15% of more than 2,000 people polled believing it would be good for the UK's international reputation.
The Department for Culture, Media and Sport (DCMS), however, says its own earlier survey found three-quarters of people asked were pleased the UK was hosting the Games.
The past two and a bit weeks can only have bolstered that support, the department believes.
"We are determined to ensure that we use the enormous excitement generated by Team GB's success in Beijing to build support for the 2012 Olympic and Paralympic Games, where our athletes will have the opportunity to shine again," a spokesman said.
The DCMS also believes Britain's haul of 19 golds in Beijing, and 47 UK medals in all, should help to make people outside London feel included in the event there in four years' time.
"Our athletes in Beijing are from every corner of the UK, and each community, town and city will have its own home-grown local hero to celebrate," the spokesman said.
The DCMS emphasises the inspiration to youngsters to take up sport as one of the public benefits of hosting the Games, on top of the regeneration of deprived parts of London and a legacy of world-class facilities.
The plan to erect of 28 giant TV screens in towns and cities across the UK during the 2012 Games is a conscious effort to involve people outside London.
But MPs have expressed fears that public participation in 2012 could be diminished by a predominant emphasis on the elite athletes' involvement.
The Beijing performance was the UK's best since the 1908 London Games
A Commons public accounts committee report last month said: "There is a risk that, unless the activities of a wide range of public, private and voluntary bodies are properly co-ordinated, the focus on winning medals could distract the department's attention from encouraging ordinary people to participate."
Don Foster MP said: "The success of Team GB in the Beijing Olympics has been the best possible advert for London 2012."
The Liberal Democrat sports spokesman, who has been critical of 2012 planning, said that the volunteer programme was key to the British public's involvement in their own Games.
"Many local projects are already up and running and hoping to capitalise on public goodwill towards the Olympics," he said.
"Interest and expectation has been raised by our performance in Beijing. The chance to turn this into a lasting Olympic legacy for the UK must not be missed."
But Mr Foster stressed that the British public's increasing enthusiasm for 2012 would not extend to any cost rises for the Games.
The budget has already ballooned to £9.325bn - almost four times the £2.4bn estimate used at the time London was bidding for the Games.
Mr Foster said he was encouraged by Olympics Minister Tessa Jowell's pledge that the budget would not be allowed to rise further.
"Looking at ways of ensuring we maximise bang for our buck," was how the London mayor described the challenge facing organisers.
"We're not going to produce an austerity games, we are not going to run the thing down, but we are going to deliver value for money and I'm absolutely determined that we are not going to waste taxpayers' money," he said.
But people are proud to discover the vital role their lottery money played in Britons' success in Beijing, even prompting them to buy more tickets, says the body responsible for helping British competitors to international success.
"There is a kind of virtuous circle," said UK Sport head of performance communications Matthew Crawcour.
Price of success
He said that people had been impressed with the boost from lottery money to the campaigns in Sydney in 2000 and Athens four years later, but there were signs of even greater enthusiasm at Team GB's stellar achievements in Beijing.
"People are curious as to why we are doing so well, and we are able to say, 'It was your money - keep on buying the tickets,'" he said.
"People do feel very good about sport being a good cause, and delivering back the feel-good factor that we are seeing out of Beijing.
"Wit, flair, imagination and ingenuity" are promised by 2012's organisers
"The fact that people are aware that lottery money is making a massive difference means that they do keep buying tickets."
But he warned that Britain's increased success would mean tougher challenges when it hosted the Games in 2012.
"Success this time round makes it harder to deliver repeat success in four years' time," he said.
"We have begun to serve notice that we are now serious about sport, and displaced a few countries in the medals table - they are going to come back at us quite hard.
"Success doesn't necessarily make for an easy life," he added.