The League Against Imperialism grew out of discussions in the Communist International in 1924 about pursuing a policy of anti-imperialist unity. Willi Munzenburg, general secretary of Workers' International Relief, called a meeting in February 1926 in Berlin out of which a League Against Colonial Oppression was established and a conference convened in Brussels to bring together anti-imperialist organisations. Responsibility for conference arrangements in Britain fell to Reginald Bridgeman (biography in separate entry for papers of Reginald Bridgeman at DBN), who was secretary of the Chinese Information Bureau. The conference ran between 10 and 15 February 1927 with nearly 200 delegates representing 134 organisations in 37 countries. George Lansbury was elected president. At a meeting in the House of Commons on 8 April 1927 it was decided provisionally to form a British section of the League Against Imperialism with Fenner Brockway as chairman, Lansbury as treasurer and Bridgeman as secretary. Helen Crawfurd, a central committee member of the Communist Party and secretary of the British section of the Workers' International Relief, became the fourth member of an executive committee (Dictionary of Labour Biography, vii, pp.40-2).
The second world congress of the League Against Imperialism was held at Frankfurt in July 1929, in the wake of which the Labour Party declared the League to be an organisation that was ancillary to the Communist Party and excluded its members from membership of the Labour Party. Bridgeman, who fought the 1929 election for Uxbridge as Labour candidate, lost his eligibility for candidature immediately after the election and was forced to resign from the Labour Party. He was one of a number of expulsions and resignations (DBN/4/4; Dictionary of Labour Biography, vii, pp.43-4).
Between 1929 and 1932 the (British) League Against Imperalism devoted itself to the campaign on behalf of the Meerut prisoners (papers at DBN/19) and in 1933, after the rise of Nazism in Germany, the international centre of the League Against Imperialism moved to London and Bridgeman became international secretary. The League was collapsing by this stage and Bridgeman tried to rebuild, with Harry Pollitt and Shapurji Saklatvala on the international secretariat. B F Bradley became the new secretary of the British section. However, through his European contacts Bridgeman was able to discover that on the continent anti-imperialist work was almost at a standstill and his Indonesian contact in Amsterdam, Roestam Effendi, one of the four communist members of the Dutch parliament, confirmed that even there, where membership of the League stood at 900, the League had become an organisation of colonials. In Britain the League went on having conferences until the sixth and last one in 1937, after which it closed down and was superceded by the Colonial Information Bureau, for which there are papers 1934-1944 at DBN/26, including some correspondence of Ben Bradley and Harry Pollitt (Dictionary of Labour Biography, vii, pp.44-48).