Photograph albums relating to his military career, [1914-1942], notably his service in Northern Ireland, 1920, Hong Kong and Shanghai, 1930, North Africa and India, [1930-1940], and Kenya, 1940-1942, with associated papers, [1914-1942], notably a diary of C and D Companies, 1 Bedfordshire and Hertfordshire Regt, Belfast, 28 Jul-30 Jul 1920.

Papers relating to writings, broadcasts and lectures, 1969-1985, including typescripts for Evelyn Baring the last Proconsul, incorporating copy source material from 1942 and correspondence with publishers; newspaper articles, 1971-1985; and memoirs of boyhood and schooldays. Papers relating to conferences and travels, 1965-1982, including typescript and manuscript accounts of visits to South Africa, Swaziland, Rhodesia and Kenya in 1976, Iran in 1978, China, Hong Kong and India, 1979 and Brazil and Chile, 1980; and diary of travels, 1976-1980. Personal papers, including invitations and correspondence, 1970-1985.

Narrative of operations of 7 Division, 1918 by the Revd E C Crosse including reference to Clifford's service as Officer Commanding 95 Field Company, Royal Engineers; papers relating to Anglo-Italian Jubaland Boundary Commission, 1925-1928 including maps; British Somaliland-Ethiopia Boundary Commission, 1931-1936, including intelligence reports on French Somaliland, air survey operations, Walwal incident between Italian and Ethiopian troops, and printed reports on the work of the Commission; Chief Engineer, China Command, including report on Royal Engineers in Hong Kong, 1941-1942; Kenya-Ethiopia Boundary Commission, 1950-1957, including diaries, 1951-1955, printed reports, and maps of the boundary, 1946-1949; published articles by Clifford, 1928-1947, mainly on boundary commissions; technical manuals, 1924-1932, including surveying; publications and printed works, 1892-1952, including boundary commissions.