Donald Cape was born 6 January 1923, the son of the late John Scarvell and Olivia Millicent Cape; he was educated at Ampleforth College and Brasenose College, Oxford. In 1948 he married Cathune Johnston; they have four sons and one daughter.

Cape entered the Foreign Service in 1946. He served in: Belgrade [Yugoslavia, later Serbia], 1946-49; Foreign Office, 1949-51; Lisbon [Portugal], 1951-55; Singapore, 1955-57; FO, 1957-60; Bogota [Colombia], 1960-61; Holy See [Italy], 1962-67; Head of Information Administration Department, Foreign and Commonwealth Office, 1968-70; Counsellor, Washington [United States], 1970-73; Counsellor, Brasilia [Brazil], 1973-75; Ambassador to Laos, 1976-78; Ambassador and UK Permanent Representative to the Council of Europe, Strasbourg [France], 1978-83. Cape died on 16 June 2014.

He was awarded the CMG in 1977.