Records of the London Electric Supply Corporation Limited and successor London Electricity Board, comprising plans of Main Transmissions Networks in the London, Essex and Kent areas, 1937 - 1951; and photographs of Grove Road Sub-Station, 195-; Carnaby Sub-Station, 1952; Neckinger Sub-Station, 1958; Horseferry Road Central Bank, 1959; Barnes Substation, 1960; Beech Station 'B' Sub-Station, 1969; Cable Tunnel under Surrey Canal, 195-; and Horseferry Road and Grove Street, 1928.