He served as British High Commissioner to Pakistan, India and Australia, and was known as a specialist in the affairs of the South Asia. He joined the Dominions Office in London in 1939, and was Private Secretary to the Permanent Under-Secretary of State from April to August 1940. In August 1940 he joined the Royal Navy as an Ordinary Seaman, was commissioned in the Royal Marines in February of the following year, and ended the war as a lieutenant colonel.
James returned to the Dominions Office (which merged with the India Office in 1947 to form the Commonwealth Relations Office) in 1945, and served in South Africa, London, and Pakistan, where he headed the Deputy High Commissions in both Lahore and Karachi during the 1950s.
He then served as Deputy High Commissioner in New Delhi before returning to Pakistan as High Commissioner from 1962 to 1965. From 1968 to 1971 he served once more in New Delhi, as High Commissioner, and was appointed High Commissioner to Australia in 1971.
He retired from the Diplomatic Service in 1976.