[1] He was then given the opportunity to read Oriental Languages at Balliol College, Oxford as an apprenticeship to a career in the diplomatic service and achieved a First Class degree.

Parsons joined the Foreign Office in 1954 and served in the British embassies in Ankara, Amman, Cairo and Khartoum, and was Political Agent in Bahrain 1965–69.

He was Counsellor in the UK Mission to the United Nations in New York City 1969–71 and Under-Secretary, Foreign and Commonwealth Office, 1971–74.

[2] In 1979 he was appointed UK Permanent Representative to the United Nations; in April 1982 after the outbreak of the Falklands War he tabled a resolution which was adopted as United Nations Security Council Resolution 502 demanding an immediate cessation of hostilities and a withdrawal of Argentine forces.

Parsons retired from the Diplomatic Service in 1982 and was part-time special adviser to the then prime minister, Margaret Thatcher, on foreign affairs 1982–83.