Background
Stewart was born in Melbourne into a wealthy Australian family with pastoral interests in the Bathurst district of New South Wales. He was a great grandson of Major General William Stewart (1769–1854) Lieutenant Governor of New South Wales from 1825 to 1827.
Education
He attended an English language school and then studied art
Career
The family moved to Paris when Stewart was in his late teens. He mixed in literary circles and met Pamela Hansford Johnson and Dylan Thomas. When the Second World War broke out he joined the British army and served as an officer in the artillery in India and Burma.
After his divorce from Pamela Hansford Johnson, Stewart married Doreen Ellen Coulling in 1950 (1d 1952).
In 1953 he published The Cloak and Dollar War, the first book to be written about the Central Intelligence Agency, described as a revelatory text. Stewart returned to Australia in 1955 and worked in Sydney as a journalist for the mining and construction industry.
He retired to Bathurst in 1983 where he died on 15 February 1999.
Membership
With other members of his family now based in England, Stewart settled in London where he worked from time to time as a journalist and became involved in radical politics.