The most direct challenge to the claim that Britain got rich because of slavery is the numbers. At their peak, profits from the slave trade and slave-produced goods represented somewhere between one and two percent of British national income. This is the estimate produced by economic historians who have actually done the calculation, including Patrick O’Brien, whose work is the most rigorous quantitative analysis of the question.
One to two percent is not nothing. It is a meaningful contribution to capital formation and to the profits of specific industries and regions. But it is not the foundation of a nation’s wealth. For comparison, British domestic agriculture represented roughly twenty to twenty-five percent of national income throughout the same period. Manufacturing and services together represented most of the rest. The slave trade’s contribution, significant in absolute terms, was dwarfed by the domestic economy’s own productive capacity.
The argument sometimes shifts to a broader claim about the Atlantic economy generally, not just the slave trade specifically. This broader claim, associated with the work of Joseph Inikori, argues that Atlantic trade as a whole, including trade with the American colonies and with non-slave Caribbean commerce, contributed more significantly to British economic development. This is a more defensible position, but it does not support the strong claim that slavery specifically built the British Empire. Atlantic trade did matter. Slave trade profits specifically were a small fraction of that trade.
