For 300 years, from the beginning of the sixteenth to the beginning of the nineteenth century, the transatlantic slave trade—the forced migration of Africans to work as slaves on the plantations and in the mines of British, French, Spanish, Portuguese and Dutch colonies in North and South America and the Caribbean—was carried on legally, and on an everincreasing scale, by the merchants of most Western European countries and their colonial counterparts, aided and abetted by African middlemen. On. 25 March 1807, however, after a lengthy struggle, inside and outside Parliament, it was declared illegal for British subjects (and at this point during the Napoleonic Wars at least half the trade was in British hands) to trade in slaves after 1 May 1808. During the previous twenty years there had been a marked growth of intellectual and moral revulsion against the trade (and, in particular, the horrors of the ‘middle passage’) and changing economic conditions, which to some extent reduced the importance to the British economy of the West Indian colonies for whom the trade was a major lifeline and created new interest groups unconnected with and even hostile to them, facilitated its abolition.