Gavin Hewitt was born on 19 October 1944, the son of George Burrill and Elisabeth Murray Hewitt. He was educated at George Watson’s College, Edinburgh [Scotland] and the University of Edinburgh (MA). In 1973 he married (1st), Heather Mary Clayton (marriage dissolved 2009), having two sons and two daughters; then (2nd), in 2015, Amanda Harvie.

Hewitt began in the Ministry of Transport, 1967–70, then was seconded as Third, later Second, Secretary to the UK Delegation to the EEC, Brussels [Belgium], 1970–72. He then joined the Foreign and Commonwealth Office in 1972 and his diplomatic career included: First Secretary, Western European Department, FCO 1972-73; First Secretary, British High Commission, Canberra [Australia], 1973–78; Personnel Policy Department, FCO, 1978–81; First Secretary and Head of Chancery, HM Embassy, Belgrade [Yugoslavia], 1981–84; Member, Joint FCO/BBC Review Group, BBC External Services, 1984; Counsellor on loan to Home Civil Service, Northern Ireland, 1984–87; Counsellor, Head of Chancery and Deputy Permanent Representative, UK Mission to United Nations, Geneva [Switzerland], 1987–91; Head, SE Asia Department, FCO, 1992–94; Ambassador to Croatia, 1994–97; Ambassador to Finland, 1997–2000; Ambassador to Belgium, 2001–03.