About 20 Grosvenor Square

20 Grosvenor Square is a 200,000 gross sq ft derelict site in the heart of Mayfair and St James’s. The current building was constructed in the 1930s and served for decades as the US Naval headquarters. In the Second World War, General Dwight Eisenhower used the building as his military headquarters.

Mayfair, named after the fortnight-long ‘May Fair’ event which took place in the area between 1686 and 1764, and St James’s, named after the Royal Palace, have long been synonymous with the world’s finest arts, fashion and lifestyle brands. The area is home to Savile Row, Sotheby’s and Christie’s, as well as some of Europe’s leading art galleries and jewellers.

  • 1710

    Sir Richard Grosvenor obtained a licence to develop Grosvenor Square.
  • Development works are believed to have commenced in 1721.


  • 1725

    Numbers 18-21 Grosvenor Square were built at this time, on the future site of the present Number 20. Numerous leading members of the aristocracy took up residence, establishing Grosvenor Square as one of the most fashionable residential addresses in London.
  • Buildings 18-21 were substantially redeveloped in this era, including a complete reconstruction of the original Number 21. The buildings were rebuilt in the Italianate style favoured by architect Thomas Cundy who, until his death in 1825, had been surveyor to the Grosvenor family’s London estates.


  • 1887

    Numbers 18-21 passed into diplomatic use, having been used as residences up to that point.
  • With the leases on Numbers 18-21 close to expiration, Scottish architect Fernand Billerey began designing a new building for the site to provide apartment residences for high society and their staff.


  • 1933-35

    The existing Numbers 18-21 are demolished and construction of the new Number 20, the building which presently exists on the site, is undertaken. The building is primarily residential, with some retail on the ground floor.
  • During the Second World War, Dwight D. Eisenhower requisitioned Number 20 as a military headquarters.


  • 1939-2007

    Number 20 served as the home of the US Navy Forces in Europe, and was internally redeveloped into open-plan offices and several secure rooms, replacing the apartments it was originally designed for. No original internal features are preserved.
  • The United States Government sold 20 Grosvenor Square to a consortium of private investors.


  • 2013

    Ownership of the building was sold to an international Joint Venture with planning permission to return the building to its former residential use. Finchatton was appointed by the new owners of Grosvenor Square Limited to act as Development Co-ordinator to review the existing planning consent and oversee the redevelopment of the site.