David Tatham was born 28 June 1939, son of Lt-Col Francis Everard Tatham and Eileen Mary Wilson. He was educated at St Lawrence College, Ramsgate, and Wadham College, University of Oxford (BA History), and in 1963 married Valerie Ann Mylechreest, having three sons.

Tatham entered the Diplomatic Service in 1960, and his career included the following posts; UKMIS New York [United States], 1962-63; Milan [Italy], 1963-67; Middle East Centre for Arabic Studies, 1967-69; Jeddah [Saudi Arabia], 1969-70; FCO, Near East and Middle East Departments, 1971-74; Muscat and Oman [Oman], 1974-77; Assistant Head of Middle East Department, FCO, 1977-80; Counsellor, Dublin [Ireland], 1981-84; Ambassador to Yemen Arab Republic [later part of Yemen], also accredited to Republic of Djibouti, 1984-87; Head of Falkland Islands Department, FCO, 1987-90; Ambassador to Lebanese Republic, 1990-92; Governor, Falkland Islands, and Commissioner for South Georgia and South Sandwich Islands, 1992-96; High Commissioner, Sri Lanka, also accredited to Republic of Maldives, 1996-99.