Con O'Neill (diplomat)

Sir Con Douglas Walter O'Neill, GCMG (3 June 1912 – 11 January 1988), was a British civil servant and diplomat. He was the British Ambassador to China (1955–1957) and the British Ambassador to Finland (1961–1963). He was also the British representative to the European Economic Community from 1963 to 1965 and led the British delegation which negotiated the country's entry to the EEC.

O'Neill was the second son of an Ulster Unionist MP, Hugh O'Neill, 1st Baron Rathcavan. He studied first at Eton, then at Balliol College, Oxford. He gained a fellowship at All Souls in 1935 before joining the Diplomatic Service in 1936.

In 1939, with the outbreak of World War II, he entered the Army Intelligence Corps. He joined the German Section of the Political Warfare Executive, during which time he would interrogate Hitler's former deputy, Rudolf Hess. He left the army for the Foreign Office in 1943. During 1946 and 1947 he was a leader writer for The Times. He re-entered the foreign service in 1948.

His daughter Onora is now Baroness O'Neill of Bengarve.