The 7,000 sq m public square project forms the last phase of the £500m station redevelopment and is understood to have attracted bids from Balfour Beatty, Morgan Sindall, Vinci and John Murphy.
Architect Stanton Williams’ plan will see the existing 1970s concourse extension removed to reveal the Victorian Grade I listed Lewis Cubbitt façade for the first time in 150 years.
The resulting open space, which will be 50% bigger than Leicester Square, will be paved with a combination of Yorkstone and granite.
Work is expected to get underway in September after the London 2012 Olympics.