Through the inter-war period, the USSR became an example of 'socialism in action' that the British labour movement could both look towards and define itself against. British visitors both criticized and acclaimed aspects of the new Soviet state between 1919 and 1925, but a consistently exceptional finding was the Soviet prison. Analysing the visits and reports of British guests to Soviet prisons, the aims of this article are threefold. Using new material from the Russian archives, it demonstrates the development of an intense admiration for, and often a desire to replicate, the Soviet penal system on the part of Labour members, future Communists, and even Liberals who visited Soviet Russia. It also critically examines why, despite such admi...