Twenty Grosvenor Square is an 8 storey building development in Mayfair, London W1.
The building is being transformed into a collection of 41 luxury residential apartments, extending the building at roof level to provide an additional two storeys. The Providence Court frontage and part of the building behind it
is to be demolished and rebuilt.
The building was erected as residential apartments in the 1930s, but was then occupied as administration offices by the US Navy during the Second World War and remained in that use (Class B1) until late 2007, since then it has been vacant until the development started.