The 1st Earl of Hertford (1718-94), was a politician, courtier and confidant to King George III. He was born the son and heir to the 1st Baron Conway of Ragley (1679-1732); was created Earl of Hertford (1750); became lord of the bedchamber (1757); was lord lieutenant of Warwickshire (1757-94); joined the privy council (1763); was ambassador to France (1763-65); lord lieutenant of Ireland (1765-66); lord chamberlain (1766-83); and was created Marquess of Hertford (1793) eleven months before his death.

Hertford purchased 15 Lower Grosvenor Street in 1740. It had been built by Thomas Ripley (1682-1758) in 1720. It is a wide house of five bays, measuring fifty-five feet in breadth. Little of Ripley's original interior now survives, though we do know that he placed the dining room in the front room on the first floor, later the location of Adam's drawing room. A plan of the house in 1763 can be seen in the Survey of London, Volume 40, p. 37. There is only one Adam drawing in the Soane Museum for this house, and this is for the drawing room ceiling. It is not known if this ceiling design was executed, as the room has now been much altered, but the survival of an Adam ceiling elsewhere - in the back parlour - suggest that Adam made other designs for this house.

From the 1790s onwards the house was variously leased and sold, and occupants included the 3rd and 4th Dukes of Portland, the 5th Duke of Rutland, the Oriental Club, the RIBA, and Lieutenant-Colonel and Mrs Keppel. In the 1930s the house was adapted for commercial occupation and is currently used as offices.

Literature:
A.T. Bolton, The architecture of Robert and James Adam, 1922, Volume II, Index p. 39; D. Stillman, The decorative work of Robert Adam, 1966, p. 96; Survey of London, Volume 40, 1980, pp. 36-38; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume I, p. 381, Volume II, pp. 169-170, 180

Frances Sands, 2011