Nicholas Bayne was born 15 February 1937, son of Captain Ronald Bayne, RN and Elisabeth Ashcroft. He was educated at Eton College and Christ Church College, University of Oxford (MA, DPhil). In 1961, he married Diana Wilde, having two sons (and one son deceased).

He entered the Diplomatic Service in 1961, and served in the following posts: British Embassy in Manila [Philippines], 1963-66, and Bonn [Germany], 1969-72; seconded to HM Treasury, 1974-75; Financial Counsellor, Paris [France], 1975-79; Head of Financial, later Economic Relations, Department, Foreign and Commonwealth Office, 1979-82; attached to Royal Institute of International Affairs, 1982-83; Ambassador to Zaire [later the Democratic Republic of the Congo], 1983-84, also accredited to the Congo, Rwanda and Burundi, 1984; seconded to Civil Service Selection Board, 1985; Ambassador and UK Permanent Representative to Organisation for Economic Co-operation and Development (OECD), Paris, 1985-88; Deputy Under-Secretary of State, FCO, 1988-92; High Commissioner to Canada, 1992-96; Chairman, Liberalisation of Trade in Services Committee, British Invisibles, 1996-2000.