Lord Duncan-Sandys was born 24 January 1908, the only son of Captain George Sandys, formerly MP for Wells, and Mildred. He married Diana Spencer-Churchill, daughter of Sir Winston Churchill, in 1935 and they divorced in 1960 (she died 1963). They had one son Julian and two daughters. His second marriage was in 1962 to Marie-Claire, formerly Viscountess Hudson, and they had one daughter. Lord Duncan-Sandys died 26 November 1987.

Lord Duncan-Sandys entered the Diplomatic Service in 1930. He served in the Foreign Office and the British Embassy, Berlin. He was Conservative MP for the Norwood Division of Lambeth, 1935-45, and for Streatham, 1950-74. He was a member of the National Executive of the Conservative Party, 1938-39. He was a co-founder of the Air Raid Protection Institute (later the Institute of Civil Defence) in 1938. He was disabled on active service in 1941 and was then Financial Secretary to the War Office, 1941-43, Parliamentary Secretary for the Ministry of Supply, responsible for armament production, 1943-44, Chairman of the War Cabinet Committee for defence against German flying bombs and rockets, 1943-45, and Minister of Works, 1944-45. After the war he was Minister of Supply, 1951-54, Minister of Housing and Local Government, 1954-57, Minister of Defence, 1957-59, Minister of Aviation, 1959-60, Secretary of State for Commonwealth Relations, 1960-64, and also Secretary of State for the Colonies, 1962-64. He founded the European Movement in 1947and was Chairman of the Parliamentary Council of European Movement, 1950-51. He was a member of the Parliamentary Assembly of the Council of Europe 1950-51 and in 1965. He founded the Civic Trust in 1956 and was later its President. He was also a member of the General Advisory Council at the BBC, 1947-51, a Director of the Ashanti Goldfields Corporation, 1947-51 and 1966-72. He received a number of awards including the Grand Cross, Order of Merit, from Italy, 1960, the Order of Sultanate of Brunei, 1973, the Medal of Honour, City of Paris, 1974, the Gold Cup of the European Movement, 1975, the Grand Cross of Order of Crown, Belgium, 1975, Commandeur, Légion d’Honneur, France, 1979 and the Grand Cross, Order of Merit, Federal Republic of Germany, 1981.