In 1938, the embassy was moved to 1 Grosvenor Square (which later housed part of the Canadian High Commission). During this time, Grosvenor Square began to accommodate several U.S. government offices, including the headquarters of Supreme Allied Commander, General Dwight D. Eisenhower, and the European headquarters of the United States Navy. Following World War II, the Duke of Westminster donated land for a memorial to wartime President Franklin D. Roosevelt. Several additional statues and memorials related to the American and British relationship remain in Grosvenor Square.
The next chancery, also on Grosvenor Square, was designed by Finnish Americanmodernist architect Eero Saarinen and constructed in the late 1950s, opening in 1960. The United States paid only a symbolic peppercorn rent to the Duke of Westminster for use of the land
Interesting facts...
When the US wanted to build its new embassy in 1960, they naturally assumed they could buy the freehold. The Grosvenor Estate (the Dukes of Westminster, who own Mayfair) reportedly replied that the Americans could only purchase the land if former colonial estates seized after the American Revolution were returned to the Grosvenors—a diplomatically impossible condition. So instead the US agreed to a 999‑year lease for a peppercorn (one literal peppercorn per year), keeping the symbolic feudal fiction while the Grosvenors retained ultimate control.
