Born in 1909,[1] he was the only son of the ninth baronet Sir Alexander Sharp Bethune and his wife Elizabeth Carnegie Maitland-Heriot.
His father had successfully claimed the baronetcy, dormant since the death of Sir William Sharp, 6th Baronet in 1780.
His sister Evelyn was the mother of Sir Alastair Pilkington, developer of float glass.
[2] Following an initial job with Quaker Oats in the USA which came to an end when foreign workers were deported in 1934, he joined the Lord &Thomas advertising agency in London.
On the outbreak of World War II, he was recruited for the Foreign Office, serving in Jugoslavia and the Soviet Union.