The son of Robert Wallace Stewart, author and lecturer, and Eva Stewart née Blaxley, Stewart was born in Bromley and educated at Brownhill Road Elementary School, Catford, Christ's Hospital and St. John's College, Oxford, where he graduated with a first class BA in Philosophy, Politics and Economics in 1929 [REF].
While at university, Stewart was President of the Oxford Union, and of St John's Labour Club (1929).