The Socialist Organisation of Working People (SOP, Czech: Socialistická organizace pracujících) is a Trotskyist political group in the Czech Republic established in 1998 after a split in the group affiliate to the International Socialist Tendency, Socialist Solidarity. . It is a section of the League for the Fifth International.
In their words: "SOP follows revolutionary traditions of Marx, Engels, Lenin and Trotsky, striving to build a revolutionary worker's party". They established an independent youth group, called REVO, in 2000. Revo had a split in 2006.
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