She was born at 89 Priory Road, West Hampstead, London NW6. Her father was Meyer Max Heinemann, a merchant banker, and Selma Schott, both non-Orthodox Jews from Frankfurt, Germany. Heinemann was educated at Roedean School and at King Alfred School in London, and read English at Newnham College, Cambridge from 1931, later graduating from Cambridge University with a BA with first class honours. She was the lover of John Cornford, while a student at the University of Cambridge. The historian Eric Hobsbawm, who was also there at the time, wrote "she probably had more influence on me than any other person I have known."
After Cambridge she taught 14-year-old girls at Cadbury's Continuation School in Bournville, now Bournville College, on day release from the chocolate factory. In the CPGB she worked in the Labour Research Department from 1937.
In 1959 she resumed teaching at Camden School for Girls and then Goldsmith's College from 1965-77. In 1976 she was made a Fellow of New Hall, Cambridge. She was still teaching at New Hall up to 1989 and stayed with the CPGB until it was dissolved in 1991.
- Britain's coal: A Study of the Mining Crisis, Left Book Club, 1944
- Wages Front, 1947, Labour Research Department
- Coal must come first, 1948, prepared for the Labour Research Department
- The Tories and how to beat them, Communist Party, 1951
- The Adventurers, 1960 (novel)
- Britain in the Nineteen Thirties, 1971 (with Noreen Branson)
- Experiments in English Teaching - New Work in Higher and Further Education 1976 (editor with David Craig)
- Culture and Crisis in Britain in the 30s, 1979 (with Jon Clark, David Margolies and Carole Snee)
- Puritanism and Theatre: Thomas Middleton and Opposition Drama under the Early Stuarts, 1980
- History and the Imagination - Selected Writings of AL Morton, 1990 (editor)
- "Website of Graham Stevensonis". Retrieved 5 October 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>[unreliable source?]
- H Gustav Klaus: "Heinemann, Margot Claire (1913–1992)", Oxford Dictionary of National Biography, Oxford University Press, 2004, accessed 5 May 2014
- Goldsmith, Maurice (1980). Sage: A Life of J D Bernal. London: Hutchinson. ISBN 0-09-139550-X.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- David Margolies and Maroula Joannou, editors (2002) Heart of the Heartless World: Essays in Cultural Resistance in Memory of Margot Heinemann