When I heard that the company Becoming Green was paying prisoners from Prescoed open prison just 40p an hour to man its call centre in Cardiff, the first thing that came to mind was The Shawshank Redemption. In the film, the warden of Shawshank prison, Samuel Norton, legally employs prisoners working inside the prison for below the minimum wage. But, without increasing their pay, he farms them out to private firms who are then able to undercut the cost of civilian labour and share their skimmed-off profits with him.

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