The real estate asset manager, a unit of AXA SA, said the project has a target completion date of 2019.

Since the June 23 referendum, the ability of London to maintain its position as Europe's biggest financial services centre has been called into question.

However, in a statement, AXA IM said its confidence was based on the broad range of amenities and types of space the development would offer, as well as its location in the City of London: "notwithstanding the current uncertainties created by the EU Referendum."

Britain's construction industry was seen as likely to face cost pressures from Brexit, as many materials are imported from elsewhere in the EU. Many construction workers also come from Europe and may find Britain a harder place to work in future.

The economy has weathered the initial Brexit shock better than many economists had feared, but the Bank of England expects construction to be one of the hardest-hit sectors.

(Reporting by Abinaya Vijayaraghavan in Bengaluru; Editing by Toby Chopra)