Aldred was born in Clerkenwell, London. His father was a 22-year-old lieutenant in the Royal Navy, and his mother was Ada Caroline Holdsworth, a 19-year-old parasol maker. Although Ada was socially unacceptable to the young naval officer, he married her shortly before Guy's birth. After the wedding, he left her at the church to return to his mother. Guy Fawkes night, 5 November, gave Guy his forename. Guy was brought up in the home of Ada’s father, Charles Holdsworth, a Victorian radical. He attended the Iron Infant's School in Farringdon Road, later moving to the Hugh Middleton Higher Grade School, where he was presented to the Prince of Wales because he was the youngest pupil. One of his fellow pupils was the son of Hermann Jung, the Swiss watchmaker and one-time activist in the First International. His first adventures in propaganda were with the Anti-Nicotine League, the Band of Hope, and the total abstinence movement, and he remained an abstainer in these respects all his life.