Wintringham's training methods were mainly based on his experience in Spain. He even had veterans who had fought alongside him in Spain who trained volunteers in anti-tank warfare and demolitions. He also taught street fighting and guerrilla warfare. He wrote many articles in "Picture Post" and the "Daily Mirror" propagating his views about the Home Guard with the motto "a people's war for a people's peace". The British Army still did not dare trust Wintringham because of his communist past. After September 1940, the army began to take charge of the Home Guard training in Osterley and Wintringham and his comrades were gradually sidelined. Wintringham resigned in April 1941. Ironically, despite his activities in support of the Home Guard, Wintringham was never allowed to join the organisation itself because of a policy barring membership to Communists and Fascists. In 1942, Wintringham proceeded to found a Common Wealth Party with Vernon Bartlett, Sir Richard Acland and J. B. Priestley. He received 48 percent of the vote at the Midlothian and Peebles Northern by-election in February 1943, previously a safe Tory seat. In the 1945 general election he stood in the Aldershot constituency, the Labour Party candidate standing down to give him a clear race against the incumbent Conservative MP. His wife Kitty stood in the same Midlothian constituency that he had come so close to winning two years earlier, but neither was elected. After the war Wintringham and many of the founders of Common Wealth left and joined the Labour Party, suggesting the dissolving of CW. In his later years he worked mainly in radio and film, both producing documentary and critical programmes and writing criticism. He continued to write about military history, opposing the use and development of atomic weapons and championing Mao's China and Tito's Yugoslavia over the monolithic bureaucracy of the Soviet Union. While he recognised and opposed the purges and repression that marred the achievements of the Soviet Union, he never understood that Stalin himself was complicit or responsible for them. His later campaigns and writing were mainly centred on the formation of a 'World Guard' a neutral volunteer force (initially) to police Palestine and the partitioned India, and to be at the disposal of the United Nations. Tom Wintringham died on 16 August 1949, aged 51, after a massive heart attack while he was staying with his sister at her farm at Owmby, Lincolnshire.