London's Olympic legacy not yet assured
Legacy. It is now a prerequisite for any potential Olympic host. And it was London's successful bid for the 2012 Olympics which set the precedent. Rewind to that triumphant day back in July 2005 and speeches from Sebastian Coe and his team were littered with references to the 'L' word.
In a nutshell, Coe promised London would not only regenerate a run-down part of east London but use the 2012 Games to increase sporting activity in Britain and around the world, particularly among the young. He also promised to re-engage the world with the Olympic movement. And he promised none of the costly venues would become white elephants.
It was a bold vision but proved to be an irresistible argument for the International Olympic Committee, one that ultimately gave London the edge over rivals Paris and Madrid.
But while much hard work has been done and some considerable progress has been made, legacy has consistently been the one area organisers and ministers have struggled with over the last six-and-a-half years.
To get a clearer idea of the difficulties with delivering an Olympic legacy, I am producing a series of films and radio reports on previous hosts, starting with the Australian city of Sydney.
The successful hosts of the 2000 Games, Sydney has been the best template for London's planning. The cultural, economic and sporting parallels are obvious, while the regeneration of Homebush was a clear inspiration for the redevelopment of Stratford.
I travelled to Sydney in January to see, 12 years on, what lessons there might be for London.
Although Sydney won its bid for the Olympics at a time when legacy was not as important, organisers hoped the Games would nevertheless bring lasting benefits afterwards.
The physical legacy of the Games at Homebush - or Sydney Olympic Park, as it is now known - is clear.
The main stadium was reduced from 110,000 seats to 80,000 following the Games and, tellingly perhaps, the running track was removed. It has proved to be a shrewd move as the privately-run enterprise, known as the ANZ Stadium, now hosts 50 different events a year, mostly field sports.
While I was in Sydney, I saw the first international cricket match to be played at the ANZ Stadium, between Australia and India. It was a rainy night but the game still attracted 60,000 people.
Daryl Kerry, the venue's chief executive, told me if there was one thing London should take from Sydney's experience it is that decisions cannot be taken to satisfy the needs of a two-week event. They have to be made for the long-term benefit of the city and country, something the Olympic Park Legacy Company will no doubt be reflecting again as they await another round of bids for the main stadium next week.
Elsewhere around the Sydney complex, the picture is more mixed.
The aquatics centre was always designed as a community facility. The main 50m pool was retained for schools, clubs and elite swimmers, but there is also a second leisure pool and water fun park. Since it opened in 1997, 17m people have used the facility, which covers its costs.
However, the park, which also houses a national showground, an indoor sports and concert arena and a smaller athletics stadium with a capacity of 5,000, needs a public subsidy of more than £35m a year.
The New South Wales government insists it is worth it. But it was not until 2006 that Sydney developed a proper legacy strategy for the park. It now has clear plans for 2030, with residential and business developments already under way. After a stuttering start, it appears the site is now moving in the right direction.
But in other areas the experience has not been so successful.
On tourism, for example, the Games were supposed to drive a boom in visitor numbers. Instead, they actually declined.
In fairness, the terrorist attacks on New York in 2001 and the SARS outbreak had a negative impact. But tourism officials I spoke to insist that Australia also failed to capitalise on the feelgood factor the Games delivered.
Some, like Andrew McEvoy, the head of Tourism Australia, say that instead of investing in worldwide marketing campaigns to drive home the message, Sydney sat back and expected the world to come.
Only now are the figures increasing from 2000 levels, thanks mainly to an increase in visitors from China, a sign that Australia's economy is moving closer to Asia and away from Europe and America.
Jeremy Hunt, the culture secretary and cabinet minister responsible for the London Olympics, will this week launch a new domestic campaign to use the Games to encourage people to explore the United Kingdom as a holiday destination.
Agencies Visit Britain and Visit England insist £2.48bn will be generated for the tourism industry by the Olympics. Others are more sceptical, arguing the Games will actually deter people from visiting London.
In participation terms, too, the picture is bleak. Australia has an image as a sports-mad country. Yet academics say the idea that hosting the Olympics led to an increase in people getting fit or playing sport is a "myth". Surprisingly, Australia shares Britain's problems with obesity.
London organisers and government ministers say they are aware of the problems experienced in Sydney, still the most memorable Olympics of the last two decades. They must be because they promised to deliver even more from the 2012 Games.
David Bond's special three-part series on Olympic legacy will appear on BBC1's Six O Clock News, News at Ten and Radio 4's Today programme.