During the Donoughmore period of political experimentation (1931-48), several Sri Lanka leftist parties were formed. Unlike most other Sri Lankan parties, these leftist parties were noncommunal in membership.

Working-class activism, especially trade unionism, became an important political factor during the sustained economic slump between the world wars. The first important leftist party was the Labour Party, founded in 1931 by A.E. Goonesinha, but this had drifted into communalist strike-breaking action by 1937. Three Marxist oriented parties--the Ceylon Equal Society Party (Lanka Sama Samaja Party--LSSP), the Bolshevik-Leninist Party, and the Communist Party of Sri Lanka (CPSL)--represented the Left proper. They grew out of the Youth League movement, the struggle to get funds for Sri Lankan ex-servicemen, volunteer work during the Malaria Epidemic and the anti-colonial struggle of the 1930s, which culminated in the call for full independence (eschewed by D.S Senanayake and others of the elite). All three were divided on both ideological and personal grounds. The Soviet Union's expulsion of Leon Trotsky from the Communist Party after Lenin's death in 1924 and Stalin's subsequent decision to enter World War II on the Allied side exacerbated these differences, dividing the Communists into Trotskyists and Stalinists. The Lanka Sama Samaja Party (Sri Lanka Equal Society Party - LSSP) is a trotskyist political party in Sri Lanka. ... CPSL May Day poster in Kandy CPSL Kandy provincial election candidate, CYF President Raja Uswetakeiyyawa Communist Youth Federation The Communist Party of Sri Lanka is a communist political party in Sri Lanka. ... Red blood cell infected with Malaria (Italian: bad air; formerly called ague or marsh fever in English) is an infectious disease which in humans causes about 350-500 million infections and approximately 1. ... In epidemiology, an epidemic (from Greek epi- upon + demos people) is a disease that appears as new cases in a given human population, during a given period, at a rate that substantially exceeds what is expected, based on recent experience (the number of new cases in the population during a... Look up élite and elite in Wiktionary, the free dictionary. ... Leon Trotsky ▶ (help· info) (Russian: Лев Давидович Троцкий; also transliterated Leo, Lev, Trotskii, Trotski, Trotskij and Trotzky) (October 26 (O.S.) = November 7 (N.S.), 1879 – August 21, 1940), born Lev Davidovich Bronstein (Лев Давидович Бронштейн), was a Bolshevik revolutionary and Marxist theorist. ... Trotskyism is the theory of Marxism as advocated by Leon Trotsky. ... Stalinism is a brand of political theory, and the political and economic system implemented by Joseph Stalin in the Soviet Union. ...

The LSSP, formed in 1935 and the oldest of the Sri Lankan Marxist parties, indeed of all existing Sri Lankan parties, took a stance independent of the Soviet Union, becoming affiliated with the Trotskyist Fourth International, which was a rival of the Comintern. Its two representatives in the State Council, Philip Gunawardena and Dr N.M. Perera, were a thorn in the side of the British colonial administration. Most LSSP leaders were arrested during World War II for their opposition to what they considered to be an "imperialist war." However, they managed to escape and the LSSP's underground work continued throughout the war. The party's propaganda was a vital element in the mutiny of the Ceylon Garrison Artillery on the Cocos Islands in 1942. It was the main opposition party after the general elections of 1936, 1947 and 1956, the second largest party in Parliament after the general elections of 1947, 1956 and 1970. For the left communist Fourth International, see Communist Workers International. ... The Comintern (from Russian Коммунистический Интернационал (Kommunisticheskiy Internatsional) – Communist International), also known as the Third International, was an independent international Communist organization founded in March 1919 by Lenin, Trotsky and the Russian Communist Party (bolshevik), which intended to fight by all available means, including armed force, for the overthrow of the international... State Council or National Council is the name of a major governmental body in some countries. ... Nanayakkarapathirage Martin Perera, better known as N. M. Perera (6 June 1905 - 14 August 1979) was one of the leaders of the Sri Lankan Trotskyist Lanka Sama Samaja Party (LSSP). ... Imperialism is the policy of extending the control or authority over foreign entities as a means of acquisition and/or maintenance of empires, either through direct territorial or through indirect methods of exerting control on the politics and/or economy of other countries. ...

Although in more recent years, the LSSP has been considered a politically spent force, gaining, for example less than 1 percent of the vote in the 1982 presidential elections, it has nevertheless been touted as the world's only successful Trotskyist party. This was because it participated in Government and because it has played a role far larger than its electoral success would suggest, having been ideologically hegemonic in the period 1936-1977. The 1972 Republican Constitution was drafted by Dr Colvin R de Silva, an LSSP Minister and the country's leading lawyer. Dr. Colvin R. de Silva (-1987) was a Trotskyist leader and lawyer in Sri Lanka. ...

The CPSL, which began as a Stalinist faction of the LSSP that was later expelled, formed its own party in 1943, remaining faithful to the dictates of the Communist Party of the Soviet Union. The Bolshevik-Leninist Party was formed in 1945 as another breakaway group of the LSSP, which reunited with its parent in 1950.

The leftist parties represented the numerically small urban working class and the larger rural working class concentrated in the plantations and mines. Partly because these parties operated through the medium of trade unionism, they lacked the wider mass appeal needed at the national level to provide an effective extra-parliamentary challenge to the central government. Nonetheless, because the leftists occasionally formed temporary political coalitions before national elections, they posed more than just a mere "parliamentary nuisance factor." In 1953 it was the left who summoned the 'Hartal' of 1953 which led to the resignation of the Prime minister, Dudley Senanayake. Hartal is an Indian term for strike action, used often during the Indian independence movement. ...