LONDON (Reuters Life!) - The roof of the main 2012 Olympic stadium began going up this week -- a symbolic stage in Britain's preparations for the Games -- but doubts remain over a long-term tenant.
The first 30-meter steel section was lifted into place on the showpiece 500-million pound ($715.4 million) stadium, taking its height to almost 37 meters(120 ft) above podium level.
The roof should be finished in nine months' time and the entire stadium by the Summer of 2011.
"The construction of the roof starts to give a real indication of the height of the structure," said John Armitt, chairman of the Olympic Delivery Authority (ODA), responsible for building the venues.
"People can start to see for themselves how the Olympic Stadium will look during the Games."
The stadium will host track and field events as well as the opening and closing ceremonies.
But concern remains about its legacy after leading football clubs ruled out moving in because of its size and the retention of the athletics track around the pitch.
The stadium's 80,000-seating capacity will be reduced to 25,000 after the Games -- too few for a Premier League football club -- and fans do not like being so far from the field of action.
London's winning bid promised the International Olympic Committee (IOC) that an athletics track would be part of the legacy.
Talks have taken place with rugby clubs while lower league football clubs could also be interested in using the stadium.
"My instinct is that we have got to work jolly hard not to have a white elephant," said Dee Doocey, chair of the London Assembly sport and tourism committee.
"I have real concerns ... which will remain until somebody takes over the legacy and somebody comes up with the money."
A spokesman for the London Development Agency (LDA), responsible for legacy, said: "Following detailed work into the legacy uses of the main stadium, we are now looking at a mixed use, with athletics at its core, combined with a strong focus on educational and community uses.
"This work is ongoing and no final decision has been taken."
The sailing venue in Weymouth, Dorset, was the first to be completed after a 15 million pounds upgrade.
Reporting by Avril Ormsby; Editing by Steve Addison