A leading member of the Communist Party of Great Britain, his history reflected a Marxian interpretation.
After Gresham's School, Holt, Norfolk, where he was a contemporary of Benjamin Britten and Donald Maclean, and two terms at Schule Schloss Salem, under the headship of Kurt Hahn, Simon went up to Trinity College, Cambridge in 1934, becoming a leader of the University Education Society.
In 1935 he joined the Communist Party of Great Britain (as his brother Roger would do a year later) and the student Marxist Study Group.
In 1940 Simon wrote to Joan Peel, his future wife, that at Gresham's most of his creative instincts had been driven out of him or deep underground.
[2] Anne Corbett, in her obituary of Simon in The Guardian said that he came under increasing attack in the late 20th century: Simon, who to many of my generation was a humane and perceptive voice, was criticised, even reviled by critics of comprehensive schools, as an upper-class intellectual who misunderstood the needs of the working-class child.