Much of his time in the 1950s was spent campaigning against American cultural imports. “Degenerate” American culture — from horror comics to Hollywood films, via the music of Nat King Cole and Bing Crosby — was a poison seeping into British homes. In Sam’s words of the time, “Wish fulfilment, sloppy eroticism and similar features are not harmless simply because we take them for granted. They are useful aides in drugging the minds of the people while US big business goes about its plan.” Good art, in Sam’s view — and indeed, not coincidentally, Stalin’s — had to be realist and serve the interests of socialism.  Whatever emanated from the US — be it the latest Hollywood B-movie or the work of the abstract expressionists — was merely serving the interests of US big business.

David’s mother’s background could not have been more different. Both of Lavender’s parents were the younger children of mid-ranking industrialists — they would not inherit the businesses so had to find an alternative path. Her father, Wyndham, stayed in the army after the First World War, eventually retiring as a fiercely right-wing, somewhat bigoted lieutenant-colonel. His younger brother had a more illustrious military career, serving as the last commanding officer of the RAF in India and ending up as Air Marshal Sir Hugh Walmsley, KCB, KCIE, MC, DFC.

In 1930, when Lavender was seven, her mother died — an extreme reaction to an insect bite whilst she was recuperating from the birth of another girl. Lavender was sent to live with family friends, Robert and Winifred Vale, in Worcestershire.

David writes: “Life in Worcestershire was not hard. There were servants, trees to climb, and ponies. But Lavender expected continuously to be called back to a father and a family of sisters; to be returned.” That call never came. Lavender’s father remarried and started a new family. Perhaps partly as a result of this rejection, Lavender started to take strongly against her bourgeois existence and the expectations of what life would be like for an upper-middle-class woman in the 1940s. Unmarried, she gave birth to a daughter in 1945 — the Vales were not pleased.

Nevertheless, around 1950, the Vales bought Lavender a house in Parliament Hill Fields, next to Hampstead Heath. Around this time, having secured somewhere permanent to live, she joined the Communist Party. The branch she joined was the same one that Sam was a member of. They married in 1954 — in Sam’s case it was his third marriage and this one, too, would not last.

Sam left full-time party work because he had been accepted, despite his near-complete lack of qualifications, as a doctoral student at Balliol College, Oxford. His acceptance there was helped by the fact that Christopher Hill was Balliol’s Master at the time. Hill had been a party member until 1956, when he resigned over the invasion of Hungary, but nevertheless remained sympathetic and close to the Communists.  Sam’s party work was well known to Hill. After his doctorate Sam became an academic — in business studies, of all things — but he remained a party man.