Sir Frederick Archibald Warner GCVO KCMG (2 May 1918 – 30 September 1995) was a British diplomat and businessman who at the end of his career was elected to the European Parliament.
Warner was educated at Wixenford School, Wokingham, and the Royal Naval College, Dartmouth. He then went to Magdalen College, Oxford, and also studied at the University of Sheffield.
After service in the Royal Navy during the Second World War, Warner joined the Foreign Office in February 1946 as an Assistant Principal. Within a few months he had transferred to the Diplomatic Service as a Second Secretary. In 1950 Warner was promoted to First Secretary and posted to the British Embassy in Moscow.
Warner returned to a London posting at the end of 1951. He was working in the private office of Hector McNeil with Guy Burgess at the time of Burgess' defection to the Soviet Union; Burgess' wayward behaviour at the time later led to accusations that Warner should have raised concerns about him. These accusations stalled Warner's career briefly: he remained in London for five years before in 1956 he was made acting Chargé d'affaires at the embassy in Rangoon, Burma. From 1958 he was transferred to Athens, Greece. In 1960 Warner was made Head of the South-East Asia Department of the Foreign Office.