 So-called contract labourers were effectively slaves as, although the signed a piece of paper, they had no idea what they were signing.In most cases they were not paid and few were returned to their homes when the duration of the contract was over.The use of such slavery in São Tomé led in 1909 to the three leading British chocolate makers, Cadbury's, Fry's and Rowntree's, ceasing to buy cocoa beans from that colony.