I've just finished reading Slave Empire, by Padraig X Scanlon, which is a remarkable reconsideration of the role of slavery, and the
British anti-slavery movement, in the creation of the British Empire, and it makes it very clear that the British government, the British slaveholders and investors, along with the classic liberal economists like Adam Smith and David Ricardo, and most of the white British abolitionists, all agreed that abolition had to be managed so that the cost to the employer of paying daily wages to free workers in plantations and factories, both at home and in the colonies, was less than that of using enslaved labour.
"Wage labour, both agricultural and industrial, has got be cheaper than using slaves" was, it seems, baked into most capitalist theory right from the start, and a great deal of abolitionist thinking was devoted to devising ways to keep incomes low and ensure that wages stayed pretty much at near subsistence level, so that the workforce had to work pretty much full time in plantations or factories, or starve (the British, at least, really didn't want former slaves setting up as subsistence farmers, trading their surplus, because that was no use to the European investors who underwrote slavery in both the US and other European colonies and former colonies).
Buy Slave Empire: How Slavery Built Modern Britain by Scanlan, Padraic X. (ISBN: 9781472142351) from Amazon's Book Store. Everyday low prices and free delivery on eligible orders.
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Padraic X Scanlan discusses how slavery fuelled the British empire and explores the complicated motivations of abolitionists
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