When Roger Casement visited a coffee plantation in northern Angola in 1902, he described the situation there in a report to the Foreign and Commonwealth Office. He found that contract workers known in Portuguese Angola as serviçais were being brought in from the Congo Free State, sold to plantations, and then forbidden to leave the estates that had ‘bought’ them. The serviçais were paid not in cash but vouchers, which they could only use at the estate store to buy poor quality goods and rum. This ‘voucher-wage labour’ was also common in the British-run nitrate mines of northern Chile. Casement reported that the Angolan serviçais were being treated as slaves, with high death rates resulting from a shocking diet. Picked up by H.R. Fox Bourne, the secretary of the Aborigines’ Protection Society (APS), Casement’s Angola report was used to add weight to protests led by the activist-journalist E.D. Morel against conditions in the Congo Free State, run as a personal fiefdom by King Leopold II of Belgium. Casement was soon sent to investigate the situation in Congo itself, leading him to produce the report that would make him famous (before his championing of the cause of Irish independence led to his execution for treason). The abuses in Congo alarmed humanitarian groups such as the APS and the Anti-Slavery Society: William Cadbury, a director of Cadbury’s in Birmingham and a Quaker, like the rest of his family, was deeply involved in these movements and could not countenance that his company’s profits were supported by slavery: and yet supported by slavery they were, as Catherine Higgs shows.