John Stuart Mill’s comment that the British Caribbean was really a part of the British domestic economy, because almost all its trade was with British buyers and sellers, is used to make a new assessment of the importance of the 18th-century slave systems to British industrialization.
If the value added and strategic linkages of the sugar industry are compared to those of other British industries, it is apparent that sugar cultivation and the slave trade were not particularly large, nor did they have stronger growth-inducing ties with the rest of the British economy.
[Rasheed Griffith comments:] …David Eltis and Stanley Engerman strongly critique the Williams Thesis and its progeny. Suppose Williams is correct that the “slave trade” was a large contributor to (or even a necessary condition for) British industrialization. In that case, we should be able to see this in these data. But from analyzing the shipping scale of the slave trade, Eltis and Engerman show that “the largest number of slave ships to leave Britain in any 5 years was 1798–41802222ya—long after the beginning of the structural changes in the British economy that have been termed the Industrial Revolution.”
They demonstrate that in 1792 when the most slave ships sailed from Britain, there were just 204 ships. But that same year, according to the data, “14,334 vessels were registered in Britain, totaling 1.44 million tons.” This means that the “slave trade thus accounted for less than 1.5% of British ships and less than 3% of British shipping tonnage.” It may not seem intuitive, but the slave trade, even at its zenith, was a modest component of the British economy, according to these data.
According to estimates cited by Eltis, the income added by the Caribbean sugar sector was less than 2.5% of the British national income. Unambiguously, Caribbean sugar plantations did not contribute substantially more than other industries in Britain.
Moreover, Britain was not a mono-crop economy. Other industries were present—providing more to the overall national output than sugar. In the Table 1 above from Eltis and Engerman, the value-added by West Indian sugar was not substantially high to the British economy. In fact, the flax and linen industries in Ireland and Scotland grew from insignificance to generate revenues greater than those of the sugar industry in the Caribbean. According to Eltis, flax and linen “profits in this era of expansion was no doubt healthy, and a portion of them were certainly spent on infrastructure and industrial activity in England.” However, historians have not argued that British industrialization could not have occurred without Scotland or Ireland being within the Kingdom’s economic realm.