On 22 May 1787 twelve men – nine Quakers and three Anglicans – met at a central London printing shop to form a committee whose sole aim was the abolition of the British slave trade. Within twenty years, despite the opposition of the powerful West Indian lobby, they had achieved their objective. In 1834 the existing slaves of the British Empire were emancipated. It is an extraordinary tale, and Adam Hochschild, prize-winning author of King Leopold’s Ghost, does it full justice.

The vested interests the abolition committee had to overcome when it began its work were formidable. Three-quarters of the world’s population was then in bondage ‘of one form or another’: as slaves, serfs, or indentured labourers. British ships dominated the slave ‘triangle’, collecting slaves in West Africa, selling them to