John William Hamilton O'Regan, OBE (1955), was born on the 22 March 1913 and educated at Marlborough, and Balliol College, Oxford. He joined the Colonial Administrative Service in 1935 and was posted to Ceylon as a Cadet. He held junior posts in Provincial Offices in Colombo and Nuwara Eliya until 1938 when he was appointed Private Secretary to the Governor, Sir Andrew Caldecott.

In 1941 O'Regan married Caldecott's daughter, Joan, and took up the post of Assistant Government Agent in Kandy. In addition to his normal work he also undertook responsibility for the introduction and organisation of food rationing for the Kandy District, and in 1942 was appointed Chief Civil Liaison Officer to the Army Divisional Headquarters in Kandy to help ensure effective liaison between the Civil and Service Authorities in the Central Provinces.

In 1944 he became Controller of the Internal Purchase Scheme and was responsible, as Assistant to the Civil Defence Commissioner, for the organisation and enforcement of the Scheme for the Compulsory Purchase of locally grown rice for the whole of Ceylon. The following year O'Regan was appointed to the post of Assistant Government Agent, firstly in Nuwara Eliya (1945-1948), and then in Trincomalee (1948-1949) where he was additionally responsible for local relations with the Naval Base and the Commander-in-Chief of the East Indies Squadron and his staff.

After fifteen years in Ceylon, O'Regan was transferred to Jamaica in 1950 as Deputy Colonial Secretary, later re-named Under-Secretary of Administration. During the six years he held this post, about two and a half years were spent as Acting Colonial Secretary and therefore as Leader of the Legislative Council and a Member of the Executive and Privy Councils. In 1953 he was Official Adviser to the Jamaican Delegation to the London Conference.

In November 1954 O'Regan was transferred to Nigeria where he held the post of Controller of Establishments in the Western Region (November 1954-April 1957). An appointment as Permanent Secretary to the Ministry of Health and Social Welfare followed, during which time he was also a member of the Committee set up to make recommendations for the integration of Departments and Ministries. In July 1958 he was transferred to the Federal Government Service in Nigeria and was appointed Permanent Secretary to the Ministry of Works and Surveys, a post he held until his retirement from the Colonial Service in April 1962.