Eltis David and Engerman Stanley L. (2000) “The importance of slavery and the slave trade to industrializing Britain”, Journal of economic history, 60, 123-144.
How important was the American slave system to the British economy of the second half of the 18th century? According to those involved in slaving ventures there was “hardly any Branch of Commerce in which this Nation is concerned that does not derive some advantage from it” (123). But this opinion was only put forward by parties had interest in overestimating the economic significance of the slave system at a time abolition was advocated by many.
Historians have assumed that slavery helped British capitalism to make a breakthrough to industrialism and hegemony ahead of its rivals. This was included in a larger picture presenting an aggressive and relentless use of violence by the British as a key element in their path to industrialisation.
It could have been instrumental for the Industrial Revolution (IR) in four ways:
• the plantations regions in the American were a very important market for the English goods.
• supplied cheap raw material to the British industries.
• provided larger profit for the British investors.
• helped stimulate consumerism in England.
Some elements multiplied the impact of the slave system on the domestic industries:
• demand concentrated on some key industries (iron).
• re-investment of the profits in productive ventures in England (bank, factories, canals).
• colonial products (cotton) were critical for growing industries.
The actual role of slavery in the British economy
This is consistent with Wallerstein’s world-system, where peripheries sustain the development of the core. It goes also along with a vision of the English proletarians too impoverished to consume even the cheap products of their factories. The problem is that by 1670 the Barbadian planters could not have produced more than 0,5% of the GDP (127).
The economic weight of the Barbados grew from the equivalent of a small county in 1700 to a big one in 1800. And it was by far the most important of the English slaving regions. The growth rate of the Barbados was 1% per annum while in England it was 0.7% (129). Eventually, if some became rich in the Caribbean many did not and there were already many rich people in England.
The slave system in the 18th century increased only anecdotally the English productivity and specially provided merely cheaper tobacco and sugar (not heavily consumed anyway) and a few extra jobs for colons and seamen.
The share claimed by the triangular trade was trivial compared to the other branches of the long-distance trade. For its peak year (1792, long after the beginning of the IR) it accounted for 1,5% of the British ships and less than 3% of the tonnage (129).
Moreover, England was neither the first nor the only slaving power but was the only powerhouse of the IR. The French Caribbean significantly outpaced their English counterparts (in 1770, 17% more sugar, 9 times more coffee, 30 times more indigo, over all they produced in value 43% more) (130). After the independence of St. Domingue (1791), the lead was taken by Cuba, Brazil and the USA. Even the growth rate of the Caribbean relative to the metropole was less than in other European examples (e.g. Cuba/Spain).
Several other industries (including food staples) generated more profit and employment than the Caribbean sugar. Some industries growth rate was faster than sugar’s (e.g. Irish flax). It was not a strategic industry either, it provided little input to other industries (cotton production took off only by 1800) unlike coal or iron. Similarly, sugar was not the only product involved in the creation of consumerism (e.g. alcohol). One possible explanation for its supposed significance is the fact that it has been particularly well documented (resources tropism).
African slave labour was certainly the most efficient form of production in the West Indies but not the only one (native and European coerced workforce were also available and used in several instances). The argument according to which the West Indies have been a key market at the moment the British industry needed it the most overlooks that British exports were very fluid, able to find demand from Europe to Asia. Moreover, the Caribbean as a market appeared late (1780s) and it is most likely that it is the IR that boosted its rise and not the contrary (139).
The slave system was an important part of the British economy and it did help its strengthening but the IR may have taken place without it. Eventually, maybe its most singular contribution was in the rise of the myth of liberty in Europe as there were no European slaves visible. This state of mind may have been the base of the rise of the modern political structure.
 Wallerstein Immanuel (1989) The modern world-system, 3, The second era of the great expansion of the capitalist world-economy, 1730-1840’s, San Diego: Academic Press, xi-372p.