[2] Later, he studied classics, economics, and political science at Glasgow University and briefly pursued further studies at Aarhus University before joining the UK Civil Service, influenced by his experience in RAF signals intelligence.
[1][2] Mellon's early diplomatic career included postings in Germany, Denmark, and at the Scottish Office's Department of Agriculture.
[1] Stationed in Brussels, he played a crucial role in relaying detailed negotiation stances back to London until the UK successfully joined the European Economic Community in 1973.
[1] Mellon later served as the head of the Foreign, Commonwealth and Development Office's (FCO) scientific and technology department, the commercial counsellor in East Berlin, and the leader of the FCO's trade relations and export department.
[1][2] In 1983, Mellon was appointed as the British Ambassador to Denmark, a position he held for three years before his final diplomatic role as Consul-General in New York and Director General for Trade and Investment in the U.S., where he worked to promote British interests and investment.