BAM has been working up the designs for several weeks having seen off competition from Skanska, Balfour Beatty and Carillion for the project, but formal award of contract had yet to happen.
Subject to planning consent, construction could start this year, with completion in 2016.
The development provides a million square feet of space across several buildings that range from seven to 11 storeys in height. The design is by architect Allford Hall Monaghan Morris, whose director Simon Allford has described the concept as “a campus within a building”.
The offices will sit on a plinth, beneath which will be shops and restaurants.