Numbers 18-21 Grosvenor Square were built in c1728-30 at the northern end of the second largest square in London, by Edward Shepherd (c1692-1747). It is possible that this was done with assistance from Colen Campbell (1676-1729) as the façade was reminiscent of Campbell's work at 31-34 Old Burlington Street. The design was composed of three houses in a single, pedimented block. In 1730 the central house, then number 18 (later 19) was purchased from Shepherd by the 7th Earl of Thanet for £7,500, and in 1765 alterations were made to the interior of the house by Robert and James Adam for Sackville Tufton, 8th Earl of Thanet (1733-86). The 8th Earl succeeded his father in 1753, married Mary, daughter of Lord John Sackville, son of the Duke of Dorset, in 1767, and was the father of the 9th, 10th and 11th Earls of Thanet. For the 8th Earl the Adam brothers made designs for the front room or gallery, the saloon, and the Earl's dressing room (all on the first floor), and for the dining room, and the dressing room, later the morning room (on the ground floor). Harris has recorded that between June 1765 and February 1766 Thanet's bank account at Hoare's was debited £1,240.4s.10d in payments to the Adam office.

The house was sold by the Earls of Thanet in the mid-1790s to the politician Paul Benfield. Most of the rooms were redecorated in the 1880s in an interesting Adam revival style, including the dining room on the ground floor, which was given a ceiling which duplicated the centre of the ceiling from the Etruscan dressing room at 26 Grosvenor Square. The house was demolished in 1933.

Literature:
A.T. Bolton, 'Town houses of the XVIII century: number 19 Grosvenor Square - I-II', Country Life, 1-8 May 1919; A.T. Bolton, The architecture of Robert and James Adam, 1922, Volume II, Index pp. 39, 89; E. Harris, The furniture of Robert Adam, 1963, Index p. 55, p. 77; The survey of London, Volume 40, 1980, pp. 133-37; E. Harris, The genius of Robert Adam: his interiors, 2001, pp. 110, 346; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume I, pp. 308-9; S. Bradley, and N. Pevsner, The buildings of England: London 6: Westminster, 2003, p. 529; E. Harris, The country houses of Robert Adam: from the archives of Country Life, 2007, pp. 146-48

Frances Sands, 2012