In 1898 Muir became an assistant lecturer in history at the University of Manchester and the following year he was appointed lecturer in history at Liverpool. From 1906 until 1913, he was professor of history at Liverpool when he resigned to take up a visiting lectureship at the University of Punjab in India. On return to England he became professor of modern history at the University of Manchester. Between 1917 and 1919 he was a member of a commission investigating Calcutta University and Indian post-secondary education. He ended his academic career in 1921 and embarked full-time on political work.
Liberalism and politics
While at Manchester, Muir had become active in the Manchester Liberal Federation and this sparked his interest in industrial, economic and social reform. He published the book Liberalism and Industry in 1920 and in 1921 he was one of the founders of the Liberal Summer Schools, an annual, week-long, residential school to promote interest in the party and to develop innovative policies. The schools were held in alternate years at Cambridge and Oxford until 1939. The schools produced the famous Liberal ‘coloured books’ on industrial and social questions and was a source of ideas for progressives in politics. Muir was also a prominent Liberal writer contributing frequently to The Nation and the Weekly Westminster. During the 1930s, he edited the Westminster Newsletter, a weekly commentary on Liberal Party affairs. Muir stood for Parliament eight times in all in the Liberal interest between 1922 and 1935. He was elected at the 1923 general election as Member of Parliament for Rochdale in Lancashire, having been unsuccessful in that constituency at the 1922 general election However he was defeated at the 1924 election. He stood for Parliament again at five further elections, without success:
Muir was also a leading figure in the National Liberal Federation, being its chairman from 1931–33 and president from 1933–3. He was a driving spirit behind the party reorganisation of 1936, and briefly acted as vice-president of the new Liberal Party Organization. From 1936 until his death he chaired the education and propaganda committee of the LPO. He was a key contributor to the Liberal policy review of 1934 and principal author of its report ‘The Liberal Way’. Although Muir was associated closely with the progressive ideas coming out of the Liberal Summer Schools, the radical solutions for unemployment, industrial and social reform which were inspired by Maynard Keynes, Lloyd George and William Beveridge, he was also something of a classical Liberal too. He was particularly constant over Free Trade, which he always supported, and took a paternal view of Imperial and Colonial questions, in which Britain's duties to its colonies took centre stage with an emphasis on trusteeship. During the Second World War, Muir was a volunteer writer and lecturer for the Ministry of Information. He never married or had children and died at his home in Pinner, Middlesex, on 4 May 1941 aged 68.
