London This aerial image, released yesterday, shows the transformation of part of East London in preparation for the 2012 Olympics, with the shape of the stadium bowl and steel seating frame clearly visible. Doubt continues over private sector backing for the media centre but a site has already been cleared.

David Higgins, chief executive of the Olympic Delivery Authority, said: “The construction site has been a hive of activity over the last year, with thousands of workers starting work on the venues and infrastructure needed for the Games and the new communities in legacy.”

He added: “With old buildings and overhead pylons coming down, and new venues and infrastructure going up, the skyline of East London is starting to change.”

Also yesterday, Lord Coe, chairman of the London 2012 Organising Committee, welcomed the completion of the first Olympic venue. He said: “Completion of the construction work on our world-class sailing venue, three and a half years before the event, is a major milestone on our journey to 2012.

“We have put athletes at the heart of the 2012 Games and the facilities at Weymouth and Portland will provide competitors from all round the world with the best possible arena for medal-winning performances.”