Hugh Carless was born 22 April 1925, the son of the late Henry Alfred Carless, CIE, and Gwendolen Pattullo; he was educated at Sherborne School, the School of Oriental Studies, London, and Trinity Hall, Cambridge. In 1956 he married Rosa Maria, eldest daughter of Martino and Ada Frontini, Sao Paulo; they have two sons.
After serving in Paiforce and BAOR, 1943-47, Carless entered the Foreign (subsequently Diplomatic) Service in 1950. His career included: 3rd Secretary, Kabul [Afghanistan], 1951; 2nd Secretary, Rio de Janeiro [Brazil], 1953; Tehran [Iran], 1956; 1st Secretary, 1957; Foreign Office, 1958; Private Secretary to Minister of State, 1961; Budapest [Hungary], 1963; Civil Service Fellow, Department of Politics, Glasgow University [Strathclyde, Scotland], 1966; Counsellor and Consul-General, Luanda [Angola], 1967-70; Counsellor, Bonn [Germany], 1970-73; Head of Latin American Department, Foreign and Commonwealth Office, 1973-77; Minister and Chargé d'Affaires, Buenos Aires [Argentina], 1977-80; on secondment to Northern Engineering Industries International Limited, 1980-82; Ambassador to Venezuela, 1982-85.
He was awarded the CMG in 1976.