In 1947, the United Nations Security Council established the Good Offices Committee for Indonesia to sponsor negotiations between the country and the Netherlands, and Timperley was assigned as Deputy Principal Secretary (later to an Acting Principal Secretary) of the committee (from May 1948?) until 20 October 1948. Afterward, he worked for UNESCO in Paris. Leaving UNESCO in 1950, Timperley went to Indonesia as a technical advisor to the Indonesian Ministry of Foreign Affairs. However a tropical disease forced him to leave Jakarta for London in 1951. Not long after his arrival in London, he came in touch with the Religious Society of Friends and was admitted to the membership in 1952. From January 1954, he threw himself into supporting the War on Want campaign and acted as full-time voluntary office worker. He organized the first War on Want Conference in May 1954. On 25 November 1954, he was found unconscious in bed and taken to a Cuckfield hospital, but died the following day (26 November 1954). Relation with publicity department of Chinese Nationalist Party In "An Overview of Propaganda Operations of the International Information Division of the Central Propaganda Bureau of the Nationalist Party from 1938 to April 1941" held in the Guomindang Historical Documents Archive in Taipei, it is clearly mentioned that "What War Means" was a propaganda book written to fight against the enemy, edited and printed by this organization. From this fact, Shudo Higashinakano agrees with the view of Minoru Kitamura and Akira Suzuki, that Timperley's book was a propaganda of Chinese Nationalist Party. On the other hand, Hisashi Watanabe claims that Timperley had yet no connection with Chinese Nationalist Party at the time, criticizing Minoru Kitamura. On 16 April 2015, Sankei Shimbun reported the discovery of documents detailing Timperley's activities as the head of the UK Branch of the International Information Division (London), which strongly supports his involvement in the propaganda operation. Works What War Means: The Japanese Terror in China, London, Victor Gollancz Ltd,1938. (There are two editions, Left Book Club and non LBC editions.) The Japanese Terror in China, New York, Modern Age Books, 1938. Japan: A World Problem, New York, The John Day Company, 1942. Australia and the Australians, New York, Oxford University Press, 1942. Some Contrast Between China and Japan in The Light of History /10-page leaflet, London, The China Society, publication date unknown. The War on Want /5-page leaflet, London, Gledhill