World War I, he organised and led the Friends' Ambulance Unit attached to the fighting front in France (1914–1915), and was then, as a conscientious objector from 1916, adjutant of the First British Ambulance Unit for Italy, in association with the British Red Cross (1915–1918), for which he received military medals from the UK, France and Italy. Political career After World War I, Noel-Baker was closely involved in the formation of the League of Nations, serving as assistant to Lord Robert Cecil, then assistant to Sir Eric Drummond, the league's first secretary-general. According to historian Susan Pedersen "Baker was far to the left of Drummond politically, but he had the kind of formation, connections, and intimate understanding of British officialdom’s rules of the game that made for easy collaboration between the two." Noel-Baker did much of the League's early work on the mandates system. He became the first Sir Ernest Cassel Professor of International Relations at the University of London from 1924 to 1929 and a lecturer at Yale University from 1933 to 1934. His political career with the Labour Party began in 1924 when he stood, unsuccessfully, for Parliament in the Conservative safe seat of Birmingham Handsworth. He was elected as the member for Coventry in 1929, and served as parliamentary private secretary to the Foreign Secretary Arthur Henderson. Noel-Baker lost his seat in 1931, but remained Henderson's assistant while Henderson was president of the World Disarmament Conference in Geneva in 1932 to 1933. He stood for Parliament again in Coventry in 1935, unsuccessfully, but won the Derby by-election in July 1936 after the sitting Derby Member of Parliament J. H. Thomas resigned. When that constituency was split in 1950, he transferred to Derby South. Noel-Baker became a member of the Labour Party's National Executive Committee in 1937. On 21 June 1938, Noel-Baker, as M.P. for Derby, in the run up to World War II, spoke at the House of Commons against aerial bombing of German cities based on moral grounds. "The only way to prevent atrocities from the air is to abolish air warfare and national air forces altogether." In the coalition government during the World War II he was a parliamentary secretary at the Ministry of War Transport from February 1942, and served as Minister of State for Foreign Affairs after Labour gained power following the 1945 general election, but had a poor relationship with the Foreign