Aberconway House, the No. 38, South Street, Mayfair, in the City of Westminster, was constructed between 1920 and 1922 for the industrialist Henry McLaren, 2nd Baron Aberconway, in a neo-Georgian style. Aberconway House is an imposing mansion of , with an adjoining guest house with ancillary accommodation of . Both properties have a southerly aspect over and access into one of Mayfair's Secret Gardens. The official architects were Edmund Wimperis and his partner W. B. Simpson. However, 38 South Street was in fact almost entirely designed by the young John Murray Easton who was later responsible for the Royal Horticultural Society's New Hall of 1926 - 1928.