Mayor of London Boris Johnson confirmed the award and start date yesterday on the route linking Greenwich to the Royal Victoria Docks.
Mace will lead a construction team of Austrian cable car specialists Dopplemayr, Watson Steel, Scott Wilson, Buro Happold and Aedas.
The consortium hopes to deliver the scheme before the 2012 Olympics but Transport for London warned that “this remains an extremely challenging timeline for a complex project”.
TfL is also seeking commercial partners to sponsor the project, which includes the right to name the crossing. The winning bidder will be announced later this year.
The cable car, 164 feet above the river, will take around five minutes to travel between the O2 and ExCel centre and is expected to carry up to 2,500 passengers an hour.
Boris Johnson said: “This innovative airborne travel link will be a vital component in the ongoing renaissance of a vibrant easterly quarter of the Capital, providing a much needed river crossing. I am thrilled we are full steam ahead to start work on this project.”