London will be ready a year ahead of schedule to stage the 2012 Olympics, officials said yesterday, as Olympic greats gave the Games venues a test run two years to the day before the festivities open.

The head of the London organising committee, former Olympic champion Sebastian Coe, told reporters on a tour of the capital's newest stadiums that he was "really pleased" with the progress of the construction, saying it was within budget and well ahead of schedule.

"We have a stadium that is structurally pretty complete. The seats are going in and it will be finished by next year," he said.

London Mayor Boris Johnson joked that the organisers were so far ahead of the timetable that: "The really smart thing for us to do as a nation would be to hold a snap Olympics which would catch our rivals napping."

Rather than the regular attempt to outdo the previous Games, the 2012 chiefs are set on building a lasting sporting legacy for Britain and regenerating one of the most deprived parts of the capital.

So while the venues may be less spectacular than Beijing 2008, and the fireworks fewer, London 2012 hopes to leave lasting urban infrastructure and housing rarely created by sports events.

"In the long term, what we want is to turn this area of east London into a place where people are going to want to come and live and make their careers in for generations," Johnson told reporters, accompanying him and the other officials on a trip across the city.

Organisers feel they are on track to produce a well-run Games on a strict budget, in keeping with the tough economic times.

To show how far the preparations have come, US athletics hero Michael Johnson, who boasts four sprint gold medals from three Games, joined with a party of schoolchildren to test out a temporary track in the 80,000-capacity Olympic Stadium.

Its distinctive white crossed-girder architecture is well on the way to completion and the seats are already being fitted.

And British cyclist Chris Hoy, who won three golds in Beijing, was the first to test out the new Velopark, which he helped design.

As he cycled round he was being cheered by construction workers still finishing the venue.

London Mayor Johnson also used the two-year milestone to launch an appeal for 70,000 people to volunteer at the Games as everything from city guides to press officers.

"This is a once-in-a-lifetime opportunity. It is the great people of this country, with their warm welcome and 'can-do' attitude, on whom the success of our Games will depend," he said.