Hamilton Shirley Amerasinghe, CCS (18 March 1913 – 4 December 1980) was a Sri Lankan diplomat and civil servant. He was High Commissioner to India and concurrently Ambassador to both Nepal and Afghanistan (1963–1967) and Permanent Secretary of the Ministry of Finance and Treasury and the Ministry of Health. Amerasinghe served as Ceylon's Permanent Representative to the United Nations 1967 to 1980 and served as President of the United Nations General Assembly in 1976. He was also one of the leaders of the negotiations to draft the United Nations Convention on the Law of the Sea. Education Born in Colombo, on 18 March 1913 and hailing from a noble family from Galle. He was educated at Royal College Colombo and went to the Ceylon University College, he took a first class honours BA degree in Western Classics in 1934 from the University of London. Career Civil Service Amerasinghe joined the Ceylon Civil Service in 1937, starting a career that would span 44 years. As a cadet, he served in the Kegalle Kachcheri, as the Additional Police Magistrate in Kegalle and office assistant, Jaffna Kachcheri. Promoted an officer, he served in the Puttalam, Mannar and Vavuniya Kachcheri, before appointment as Secretary to the Minister of Health in 1941. He then served as Assistant Controller of Imports and Exports, Assistant Government Agent, Kegalle, Rathanapura and Matale. He was then Assistant Secretary to the Ministry of Home Affairs. In 1950, he was appointed Resident Manager of the Gal Oya Development Board in 1950. Two years later, he was sent on his first overseas appointment as Counsellor of Embassy of Ceylon in Washington, DC, from 1953 to 1955. From 1955 to 1957, he was the Controller of Establishments, General Treasury. In 1958, he became the Controller of Finance, Supply and Cadre, General Treasury. The same year, he was appointed as the Permanent Secretary to the Ministry of Nationalized Services and Road Transport as well as Chairman of the Port (Cargo) Corporation. In 1961, Amerasinghe became Secretary to the Treasury and Permanent Secretary to the Minister of Finance, succeeding his cousin Samson Felix Amarasinghe and held that post until 1963, while also serving as Official Member of the Monetary Board of the Central Bank and Alternate Governor for Ceylon in the International Bank for Reconstruction and Development. In 1963, he was appointed Ceylon High Commissioner to India and served concurrently as Ambassador to Nepal and