The Quadrant is made up of four blocks at the southern end of Regent Street at the sites of the former Regent Palace Hotel, Cafe Royal and Quadrant Arcade.
The Crown Estate, which owns property on behalf of the Queen, said it has started refitting part of the Grade II-listed Quadrant Arcade block at 7-9 Air Street (known as Quadrant 2) to provide new modern office space. Work is expected to be finished in 2015.
It has already completed the £400m transformation of Regent Palace, known as Quadrant 3, on Glasshouse Street into a mix of offices, shops, restaurants. The building includes a large branch of US retailer Whole Foods and Al Gore’s Generation Investment Management amongst its tenants.