After Gresham's School, Holt, Norfolk, where he was a contemporary of Benjamin Britten, Sir Alan Hodgkin, James Klugmann and Donald Maclean, Simon read economics at Gonville and Caius College, Cambridge.
Simon was influenced in this decision by meeting Emile Burns on the boat to the Soviet Union in 1936 - a trip with his parents.
From 1945 to 1946, he taught law at Welbeck Abbey, where soldiers with three years' service could have a month's free education.
At Welbeck he met Edmund Penning-Rowsell, another communist who became a lifelong friend and fellow wine enthusiast.
He was also on the board of Lawrence and Wishart and encouraged the publication of "Selections from the Prison Notebooks of Antonio Gramsci" in 1971.