AI-focused group Sierra is taking 41,000 square feet of offices Belvedere SW1. (Tishman Speyer) CoStar News June 11, 2026 | 7:14 AM Tishman Speyer, the global developer, owner, operator and investment manager of real estate, has signed five new leases totalling 81,000 square feet at the Belvedere SW1 campus at 123–151 Buckingham Palace Road in London's Victoria. Watch the video to learn how you can access industry leading CRE news and the data analytics you need to drive success.