Roy Denman was born in Liverpool, 12 June 1924, the son of Albert Edward Denman and Gertrude Ann Denman (née Nefyn). He was educated at Harrow Grammar School and St John’s College, Cambridge. He married Moya Frances Gabrielle Lade, 1966, with whom he had one son and one daughter.

During the Second World War, he served with the Royal Signals, 1943-6; was seconded to the Indian Army during the Burma [later Myanmar] Campaign; and was promoted to the rank of Major. After the war, he joined the Board of Trade,1948, where he was Assistant Private Secretary to the President, 1950-2. He subsequently served as First Secretary in the British Embassy in Bonn, West Germany [later part of Germany], 1957-60, and as a member, 1960-1, and Counsellor, 1965-7, of the British delegation in Geneva. He returned to the Board of Trade [later the Department of Trade and Industry and then the Department of Trade] as Under Secretary, 1967-70, and Deputy Secretary, 1970-5. During this period, he was a member of the delegation negotiating the UK's entry to the European Economic Community [EEC], 1970-2. He took up the post of Second Permanent Secretary at the Cabinet Office, with responsibility for co-ordinating European affairs, 1975-7; and then Director-General of External Affairs at the EEC Commission, 1977-82; and finally Ambassador and Head of the EEC Delegation in Washington DC, 1982-9. He was a business fellow of the John F. Kennedy School of Government at Harvard University, 1989-90.

He was appointed CMG, 1968; CB, 1972; and KCB, 1977.

He died on 4 April 2006.

His publications include: "Missed Chances: Britain and Europe in the Twentieth Century" (1996); "The Mandarin's Tale" (2002); and "Britannia and the Hun" (2005).