From the fifth-floor windows of the Olympic Park Legacy Co., the site for the London 2012 Olympic Games looks like a mock-up. Across a half-mile or so of slate rooftops, slicked black by a recent shower, the stadiums jut incongruously upwards, appearing more like temporary art installations than permanent fixtures in this deprived corner of east London.

The sense of activity outside is overwhelming. Cranes swing across the skyline and the demand for workers and materials has turned the streets near the site into a moving tapestry of fluorescent jackets and heavy goods trucks. The real work, though, is still some way off starting.

Spectacular as they hope the games will be, the organizers of London 2012 are merely using the event as a springboard for a far more ambitious project: the city’s bid was won on the back of a legacy promise to transform the social, economic and sporting futures of a generation of east Londoners.

At the heart of this urban overhaul is the largest program of home-building the U.K. capital has ever seen. The only problem is that no one will know the results of this construction marathon until long after the ceremonial torch has been carried off for its next public appearance.

“Basically, the games are a massive asset for us to launch a 25-year regeneration program from. That is what will be remembered in the long term,” says Duncan Innes, real estate director at the OPLC.

Along with his team and the Olympic Delivery Authority, Innes hopes to deliver 11,000 new homes in the years after the Games and, in doing so, change the fortunes of an area long associated with urban decay.

The public has been given various assurances about the new homes, which will form the residential backbone of the Stratford regeneration. They will be bright, exciting, new, safe, and, crucially, part of a community.

The OPLC’s website promises that the project “will take the best of ‘old’ London—such as terraced housing inspired by Georgian and Victorian architecture, set in crescents and squares, within easy walking distance of a variety of parks and open spaces.” The ambition is bold. If the various agencies involved pull it off, this area of unloved industrial dumping ground will become the most important addition to London’s residential jigsaw for decades.

The problem is that, in the past, the sporting circus that is the Olympic Games hasn’t always packed the regenerative punch that it promised. In some cases, the games have even become the catalyst for deep urban decomposition. The acres of overgrown scrub ringing the long-abandoned venues of Athens’$2 2004 Games, for example, and the virtual ghost town left in the wake of Sydney’s effort four years earlier, are testament to this.

In the case of Athens, the main cause of this grim after-the-party reality is easy to unpick: cost. In spite of delivering what the late Juan Antonio Samaranch, then president of the International Olympic Committee, described as the “best ever” Games, Athens was left facing a bill of almost £10 billion. The pressure was on to balance the books, not to plough more money into deconstructing the temporary infrastructure and building new housing developments.

The upshot is that the lasting legacy of the 2004 games is a city stuffed with expensive white elephants, debt, and a bad reputation for event management.

In other former host cities, Sydney among them, a lack of long-term planning before the games has been more of an issue than a lack of money. But the result—underused infrastructure and a bitter aftertaste—has been the same.

Nick Raynsford, chairman of Triathlon Homes, which is converting the 2012 Athletes’ Village into a 2,818-unit housing project, says the lessons of past games have been heeded.

He points out that the biggest flaw with previous games has been the focus on delivering the event itself, rather than seeing it as being part of a much wider package of urban transformation.

“Historically, people have built things like the athletes’ accommodation and thought of a use for it afterwards. The problem is that a single-tenure solution doesn’t work and it becomes a sink estate almost overnight,” Raynsford explains.

The vision for the residential future of the Olympic site at Stratford is different. From the flats in the Athletes’ Village to the upmarket townhouses by the Velodrome, the agencies involved hope to attract a ready-made community of both locals and outsiders, of impoverished and middle-class homebuyers, of single twentysomethings and large families—all living side by side in the new neighborhood.

And they have planned for it. London is the first host city to have set up a legacy company before the games—it will be in its third year by the time the first race is run next summer—and the result is that every square meter of the Olympic Park has been allocated a future purpose.

In the computer-generated depictions of the site, parkland and garden-fronted homes are bisected by sweeping walkways and implausibly clean-looking canals. On one side of the development stands the hulking glass-and-wood slatted frame of the still unfinished Westfield shopping centre, which will be the largest mall in Europe when it completes later this year.

The colorful milieu has nothing in common with the Stratford of today, which is little more than a large transport terminus surrounded by drab shops and unremarkable office buildings, stained nicotine brown by years of diesel-belching buses.

Critics of the Olympic development plans say this polarity between the dilapidated fabric of the surrounding borough of Newham and the futuristic gloss of the new town will be socially divisive.

“People have tried to build smart housing in deprived areas and they end up creating islands of prosperity,” says Ed Mead, a director at Douglas and Gordon, the estate agent.

Poverty in Newham is very real. The borough ranks as the second most deprived in England, according to the government’s Indices of Multiple Deprivation. Nearly half of its adult population is unemployed and last year the average gross weekly pay for full-time workers in Newham was £507, compared with £607 for London as a whole.

“Ultimately, you need a cohesive society and that doesn’t work by having an ivory tower at the end of the street. It just creates a sense of them and us,” adds Mead.

There are also concerns about the rising cost of living in the area close to the development. In the run-up to the games, host cities typically experience faster house price growth than the rest of the country. Barcelona, for instance, saw property prices rise 131 per cent in the five years before the games, compared with 83 per cent across Spain, according to data from the Halifax. While less marked, Athens, Sydney, and Atlanta all experienced the same decoupling from nationwide house price trends.

The OPLC, however, says the new housing will contribute to the local economy and that the benefits of the jobs and wealth generated by the development will disperse to the neighborhoods around the site.

In Newham itself, though, not all the locals are convinced the games will deliver the kind of change they have been promised.

“There is a lot of talk about the commitment and how the investment is there for the long term. The problem is that until it happens, people round here are going to be hard to convince,” says one local resident of over 30 years.

Back in the office at the OPLC, Innes agrees. He points out that London will have to follow the example of Barcelona, where the local authorities kept residents happy by starting the legacy work with a series of visible and high-profile regeneration projects. The city will get a similar dose of this urban acupuncture and Innes confesses that he and his team will be looking to score some “big early wins”.

“The overarching concern is to make the right long-term decisions on day one. We can’t make it a success in five years, but we could get it badly wrong. We will be judged on what is there many years from now, not on what we say will be there today.”