The Survival of the Nefarious Slave Trade
British traders in enslaved Africans found ways around the Slave Trade Act of 1807, while commerce flourished through the import of slave-grown cotton.

Within days of the 1807 Anti-Slavery Act coming into force, British slave traders were already deploying a number of ruses to circumvent it – as it had taken some twenty years for Parliament to pass the Act, there had been plenty of time to figure these out. In 1810 reports that British slavers, sailing under foreign colours, were still actively involved in the trade led the politician and reformer Henry Brougham to present a new bill to make the 1807 Act more effective.
Negotiations with some other European countries engaged in the ‘nefarious trade’ resulted in agreements to stop trading, or to stop trading at particular latitudes – after all, Britain did not want other countries to increase their profits from cheap slave-produced goods. Even the Prince Regent participated in this international pressure.
The Royal Navy sent vessels to intercept slave traders off the West African coast, but these ships were mostly old and not suitable for inshore sailing. Nevertheless, the Anti-Slave Trade Squadron did capture some slavers. In 1810 twenty vessels were condemned in the Vice-Admiralty Court at Sierra Leone; they were sailing ‘under Portuguese or Spanish colours’ but were in fact owned by American and British traders. Some had been built in England, but had been fitted out for carrying the slaves on the Ile de France (Mauritius). Once the captain was tried and convicted, the vessels were sold – many to local slave traders or to the agents of others. A proportion of the profits went to the British naval captain and crew, who also profited in another way: the officers of HMS Amelia, for example, kept some of the African boys freed from the slavers as their personal servants.
The London-based African Institution, the successor to the Anti-Slavery Society, estimated that by 1812 about 70-80,000 enslaved men, women and children were being exported annually from West Africa to Europe’s colonies on the other side of the Atlantic. Ships were built in Britain; if the builders felt they could evade the eyes of the law, they were fitted out for carrying slaves there. But it proved more convenient for the vessels to sail only with the goods to be traded for slaves, and receive their special fittings en route. In 1816 the Gentleman’s Magazine printed a letter signed by ‘Sierra Leone’, who argued that there had been:
... too much pro-slave-trade propaganda … It is questionable whether the Slave Trade is not actually carried on to nearly an equal extent as ever with British Capital!! notwithstanding the Acts of the Legislature and the vigilance of the Government.
The African Institution monitored the illegal trade and initiated action against some of the ships involved, such as the Commercio de Rio, which was condemned in a London court in 1810. She had been fitted out for the trade and expected to make £60,000 profit from a voyage. Another ship, the Gerona, formerly the slaver Hercules, was ‘English built’, ‘coppered’ and outfitted in Liverpool, and supposedly sold in Philadelphia with the aid of the Spanish consul there. She was condemned in Sierra Leone in 1810, but was reported as having ‘foundered’ and an insurance claim was made by the owners. However, the Institution’s records note, she later turned up at Portsmouth. In 1811 the Liverpool-based abolitionist William Roscoe wrote to Thomas Clarkson, veteran of the anti-slavery movement, that ‘while the trade is allowed to be carried on by foreign powers it will always be practicable, by sending Agents, capital and goods to fit out vessels in foreign ports’. For the next fifty to sixty years traders used these tactics, coupled with sailing under multiple flags, to make fortunes from the sale of enslaved men, women and children.

Almost all the ‘trade goods’ the ships carried were manufactured in Britain. They were usually insured by British companies and the trade was financed by British banks. If the vessel had not been fictitiously ‘sold’ en route at a convenient island, then it was sold in Brazil. The British company that owned or had built the vessel often had a partner in Brazil, Cuba, or the southern US states so the goods did not even have to be off-loaded. The vessel could then immediately set sail for the African slaving ports, under a flag of convenience – that is of a nation that had not officially banned slave trading. It was simple.
So simple that the British consuls in Brazil and Cuba were well aware of what was going on, and informed abolitionist societies and the government at home. The Consul in Rio de Janeiro wrote to Lord Palmerston on May 6th, 1838, that:
As regards British capital … the various undertakings going on in this country, which are every day multiplying, and which are for the most part the result of British enterprise, are all dependent on slave labour … Candonga Mining Co. goes into the market for its slave labour…’
Abolitionist MPs continued to raise in Parliament the many ways that Britons broke British laws regarding slavery and the trade in slaves. There were almost annual Parliamentary Commissions and more acts of Parliament – so many that they were consolidated twice, in 1824 and 1842. But the laws were weak and were not enforced.
In Africa the influence of the ongoing slave trade was devastating. As the West Indian Reporter for January 1830 pointed out, ‘Wars on the coast of Africa have been purposely excited to supply the demand for captives.’ This had been ongoing for about two hundred years, resulting not only in human loss of life but also in setting up relationships between weak and strong nations that still bear influence today. Of course, only the most productive age groups were exported from the continent. The introduction of Western manufactured goods ruined local African industries such as tin manufacturing and cotton weaving. Africans were introduced to strong European liquor: for example, almost 188,000 gallons of ‘spirits’ (mainly rum – the produce of slave labour in the Caribbean and South America) were exported to West Africa in 1834.

In 1833 an Act was passed to emancipate slaves in the British islands of the Caribbean and Mauritius. At first, West Indian planters were protected because the import duty imposed on their now free-grown sugar was much lower than on slave-grown sugar imported from places such as Cuba. However, pressure from interested groups resulted in the equalizing of duties on slave and free-grown sugar in 1848. The Reverend Dr McNiele pointed out, in a pamphlet written that year, ‘you have already heard of the rejoicings at Havannah … there were illuminations.’ He added that Lord Howden, writing from Rio de Janeiro, estimated ‘that 60,000 have been imported as slaves into the Brazils since 1847’. Not surprisingly, some of the slave-worked plantations and mines of Brazil were owned by British companies, prevented by the 1833 Act from owning slaves.
The manufacturing of cotton cloth was now central to the British economy. About 80 per cent of the 740 million lbs of cotton imported into Britain in 1852 was slave-grown in the USA. More than 90 per cent came in through Liverpool, destined for the mills proliferating throughout Lancashire, especially in and around Manchester. Cotton exports (about one-third of British exports at this time) also flowed through the same port, either as raw cotton (45 million lbs in 1842) or as cotton cloth (20 million yards exported to Africa alone in 1851). Slave-grown tobacco from Cuba and the Southern states of America – about 31 million lbs in 1838 – was unloaded at Liverpool’s docks. The revenue from Liverpool’s docks was about £250,000 by the 1850s. Thus Liverpool, which had pleaded that it would collapse without the open trade in enslaved Africans, in fact grew and grew. And much of this growth was still based on slavery and the ‘nefarious trade’.
According to one contemporary estimate, the total number of people employed directly in cotton manufacturing in the UK was 1.4 million. But a far greater number – ship builders, sailors, dockworkers, machine manufacturers, labourers on the canals and the railway linking Manchester and other cotton manufacturing towns to Liverpool, those employed in the banks, by the merchants and insurance companies – in Lancashire and beyond, were ultimately dependent on slave-grown produce for their livelihood.
The reasons behind the American Civil War are still being debated. From one perspective, it was the slave-states attempting to ensure that their highly profitable businesses, selling slave-grown produce, would not be crushed by the northern, anti-slavery states. The official British attitude was one of neutrality, but not only were millions of pounds openly collected in Britain to aid the southern states, Liverpool shipyards made a fortune out of building smallish, very fast vessels for Confederate slave-owners to circumvent the northern blockade of their ports. At least one Confederate warship was built in Britain, and one former Royal Navy vessel was sold to the south.