Sir Howard Smith (1919–96) joined the Service after a long and distinguished career with the Foreign and Commonwealth Office.
During his 32 years in the Foreign Service he held a variety of posts, including serving as the British ambassador to Czechoslovakia and the Soviet Union.
He became Director General of the Security Service in 1978. He was the first DG to be appointed from the diplomatic service; the Prime Minister of the day, James Callaghan, later explained that he had wanted "to bring someone into the office from a different culture."
Under Sir Howard's management, the Service became more deeply involved with counter-terrorist work in response to the growing threat from Northern Ireland's paramilitary groups and international terrorism. He retired in March 1981.