Westminster Council has agreed plans submitted by new owners to convert the American Embassy building in Grosvenor Square in central London into a luxury hotel as part of a £1 billion restoration of the area.

Development work is expected to begin next year when the American Embassy is due to move to its new home in Nine Elms, Battersea.

Plans submitted will see the Grade II-listed modernist block converted into a 137-bedroom, five-star hotel with a spa and ballroom for 1,000 guests.

The complex will also include residential units and restaurants.

Grosvenor Square has been America’s largest European embassy since the 1960’s. The move to Battersea will end a US association with Grosvenor Square that goes back more than 200 years. The site has long been the focus of protest against US government policy; most famously the anti-Vietnam war demonstrations of the late 1960’s and early 1970’s.

New owners, the Qatari Investment Authority sovereign wealth fund, now plan to return the ‘fortress site’ to open, expansive green space for residents and visitors alike.