A team of four architects is working up designs for the Blossom Street site on the edge of the Square Mile.
The developer confirmed the progress in its latest results which also revealed a near-term pipeline of work worth up to £1.2bn.
British land said: “We have a further 719,000 sq ft in our near-term pipeline which are projects we could commit to over the next year to eighteen months.”
Schemes in that near-term pipeline include 4 Kingdom Street in Paddington where British Land plans to start construction by the end of this year.
Demolition work is also underway at Aldgate Place where Keltbray is clearing the site on the city fringes.
British Land has teamed-up with Barratt Homes at Aldgate Place to deliver a 365,000 sq ft residential development programme.
