Between 1761 and 1808, British traders hauled 1,428,000 African captives across the Atlantic and pocketed $96.5 million – about $13 billion in value today – from selling them as slaves.
From 1500 to 1860, by very modest estimations, around 12 million Africans were traded into slavery in the Americas. In British vessels alone, 3.25 million Africans were shipped. These voyages were often very profitable. For instance, in the 17th century, the Royal Africa Company could buy an enslaved African with trade goods worth $5 and sell that person in the Americas for $32, making an average net profit of 38 percent per voyage.
Slave-owning planters and merchants who dealt in slaves and slave produce were among the richest people in 18th-century Britain, but many other British citizens benefited from the human trafficking industry.
Profits from slavery were used to endow All Souls College, Oxford, with a splendid library; to build a score of banks, including the Bank of London and Barclays; and to finance the experiments of James Watt, inventor of the first efficient steam engine.
As the primary catalyst for the Industrial Revolution, the transatlantic slave trade provided factory owners who dealt in textiles, iron, glass and gun-making a mega-market in West Africa, where their goods were traded for slaves. Birmingham had over 4,000 gun-makers, with 100,000 guns a year going to slave-traders. The boom in manufacturing provided many jobs for ordinary people in Britain who, in addition to working in factories, could be employed to build roads and bridges, and in whaling, mining, etc.