Duke entered the Indian Civil Service in 1928, and was sent to the
United Provinces of Agra and Oudh. In 1934, he transferred to the Indian Political Service and was assistant private secretary to the viceroy from 1934 to 1938 and then secretary to the governor of the
North-West Frontier Province from 1940 to 1941. From 1941 to 1943, he served as political agent in
Waziristan and from 1943 to 1947 he worked as secretary in the External Affairs Department of the Government of India at
New Delhi. In 1947, Duke transferred to the Foreign Service, and served in
Pakistan as deputy high commissioner at
Peshawar and then as counsellor at the British Embassy in
Egypt and as consul-general at
Mashhad, Iran. In 1954, he was appointed Ambassador to Jordan, remaining in the post until 1956. His final posting before retirement was as Ambassador to Morocco from 1957 to 1961. In retirement, Duke was director-general of the Middle East Association from 1964 to 1970. == Personal life and death ==