The Western European prison reforms of the 1960s and 1970s were based, among other things, on the claim that prison labour should match the conditions of free labour as closely as possible. In reality, prison labour remained forced labour and thus followed its own logic, within which social security and remuneration did not correspond to the free labour market conditions. Prisoners were not and are not workers in the true sense of the word; rather, they oscillate between forced labour and non-work. This article deals with this contradiction, which is still inherent in prison labour in many Western democracies today. Using the example of West Germany, it historicises the relationship between work and punishment behind bars and attempts to show that although the punitive nature of prison work has changed since the late 1960s, it has ultimately never been lost – despite criminal policy objectives to the contrary. It was a normative question of values: how much equality did prisoners deserve?