Slavery on an industrial scale was a major source of the wealth of the British empire, being the exploitation upon which the West Indies sugar trade and cotton crop in North America was based. Those who made money from it were not only the slave-owners, but also the investors in those who transported Africans to enslavement. In the century to 1810, British ships carried about three million to a life of forced labour.Campaigning against slavery began in the late 18th century as revulsion against the trade spread. This led, first, to the abolition of the trade in slaves, which came into law in 1808, and then, some 26 years later, to the Act of Parliament that would emancipate slaves. This legislation made provision for the staggering levels of compensation for slave-owners, but gave the former slaves not a penny in reparation.