 (Unlike him, Constance had never accepted the Moscow-imposed party line of 1939–41, which followed the Molotov-Ribbentrop pact).The cold war, particularly frozen during the years of the Korean War and McCarthyism, made it easier to maintain them.He soon became a pillar of the Communist Party Historians' Group ("intellectually my lifeline"), and also of the Hull Communist party and its associated organisations, while building a double expertise in 19th-century British economic history and labour history.