Balfour Beatty was understood to have signed a deal this week to construct the aquatics centre for the 2012 Olympic Games.
As Building went to press, sources close to the project said a price had been agreed for the Zaha Hadid-designed building, although details were still to emerge. Previous estimates suggested the scheme would cost about £213m.
The news comes as the Olympic Delivery Authority put out a tender for the handball arena, to be designed by Make Architects. The venue will be transformed into a local sports venue afterwards.
The arena is the final significant permanent building for the Games still to be tendered.