David Cameron has predicted the Olympics will benefit the UK economy by more than £13bn as he looked forward to an "inspirational" games.
The Prime Minister, on a visit to Team GB's preparation camp in Loughborough, insisted that London 2012 had to be about more than a "one-off, one-summer wonder".
Mr Osborne stressed that it had to be taken as an opportunity to boost the economy and jobs, revive sport in schools and to regenerate communities.
Despite a price tag in excess of £9bn, he said the Games should not be seen as "an expensive luxury in tough times". "It is precisely because times are tough that we have got to get everything we can out of them to support jobs and growth in the economy."
He added: "I am confident that we can derive over £13bn benefit to the UK economy over the next four years as a result of hosting the Games. I am certain that when you add in the benefits from construction the total gain will be even greater."
Speaking with just 22 days left to go before the opening ceremony, Mr Cameron said: "The next few weeks are going to be simply amazing," he said. "We'll remember them all our lives. Our children will remember them too.
"These four weeks in a British summer are going to be like no other four weeks in a British summer. They will be about making the most of our country, being everything it can be, at the centre of the world's attention."
His comments came as athletes from around the world begin to arrive in the UK ahead of the event's opening ceremony on July 27.
The Government estimates that 4.5 million extra people will visit the UK during the Games, contributing to over £2bn worth of spending from extra tourism. Their total cost is estimated at £9.3bn.
"This summer is going to be about a magnificent sporting event," Mr Cameron said. "We'll be celebrating the medals, the heroes and the heroines. It will be inspirational. We must make sure these are the inspirational games.
"But to really make the most of them we have got to make sure this inspiration is more than a one-off, one-summer wonder. It can be so much more.
"One of those special moments in our national story. A time that caught the mood. A time that lifted us. A time that created something amazing.
"There is an opportunity to regenerate communities. To bring people together as volunteers. To revive school sport. And to bring prosperity and jobs to this country.
"But the first prize is even more valuable. A national boost to our energy and inspiration, a chance to realise how great we can be and how much we can go on to achieve as a country.
"These are Britain's games, Britain's opportunity and Britain's moment. We've got to make the most of them - and we will."
Mr Cameron admitted there would be "hiccups, last-minute worries and challenges to overcome", including the pressure of crowds on London's transport system but defended the organisers.
"There is no need to think that anyone or any country could have done these Games better. We are doing these Games brilliantly and we are doing them in Britain," he said.
Turning to Britain's athletes, he added: "I want to thank every one of them for their efforts. I know they will do us proud. I'll be cheering Team GB on all the way and I know the whole country will be too."