The Atlantic Slave Trade and the Long Fight to Abolish It

The Atlantic slave trade did not end when it was outlawed. Britain banned its own trade in 1807 and abolished slavery in its colonies with effect from 1834, and in the decades between and after those dates, ships continued to carry Africans across the Atlantic in enormous numbers. Understanding abolition means understanding that gap — how long it lasted, who kept the traffic going, and what actually closed it.

It also means being careful about the arithmetic. Counts of the trade are reconstructions built from voyage records, port registers and customs papers, and they are estimates with method behind them rather than tallies.

What the numbers describe, and what they do not

The National Archives states that over three million Africans were enslaved and transported to the Americas, the Caribbean and elsewhere by British traders between the sixteenth and nineteenth centuries. That is one national carrier inside a far larger traffic involving Portuguese, Spanish, French, Dutch, Danish and other shippers, and the total depends on which voyages the compiler could document.

Two other systems are often folded into the Atlantic figure and should not be. Trans-Saharan and Indian Ocean slave trading had their own routes, chronologies, legal frameworks and records, and ran on different timescales. Merging them produces a number that describes nothing accurately. UNESCO's Routes of Enslaved Peoples programme, launched in 1994, treats them as distinct strands of a global history for exactly this reason.

The people behind any of these figures were not cargo, and the sources that call them that were written by the people profiting from the voyage. Where names survive, they survive because an owner recorded property.

The 1807 Act, and the six per cent

This is the single most clarifying statistic in the subject. Daniel Domingues da Silva, David Eltis, Philip Misevich and Olatunji Ojo, writing in the Journal of African History, calculate that the anti-slave-trade squadrons intercepted only about six per cent of the 2.8 million Africans transported across the Atlantic after 1807.

Two things follow. First, 2.8 million people were trafficked after the trade was abolished by its largest carrier — so abolition legislation and the end of the trade are separated by the better part of a century. Second, naval interdiction, which occupies a large share of the popular story of abolition, reached a small fraction of those voyages.

The same study counts approximately 180,969 Liberated Africans taken from intercepted vessels, with around 99,466 first landed at Freetown in Sierra Leone and the remainder dispersed to Brazil, Cuba, the British Caribbean and elsewhere. Its conclusion is not triumphal: nearly all of them, the authors find, were pulled at least partly into the Atlantic wage economy. Liberation from a ship was not restoration to a home.

The National Archives holds the administrative residue of this — records of the Royal African Company, the Foreign Office Slave Trade Department series, and Slave Trade Commission registers documenting tens of thousands of people who were enslaved and subsequently liberated. Those registers exist because interception created a legal process, and the process generated paper.

Enslaved people forced the question

Abolition is often narrated as the achievement of a small number of European campaigners. The record does not support that as a complete explanation.

The National Archives' teaching resource on Bussa's rebellion documents one case in detail. On 14 April 1816, enslaved people in Barbados rose under Bussa, a ranger at Bayley plantation. The rising was, in the Archives' description, carefully planned and organised by senior enslaved men and women working across several estates. Around 400 people fought. Part of the immediate trigger was a belief that the governor was returning from Guadeloupe with a "free paper" — and the underlying expectation had been created by the 1807 abolition of the trade itself.

The reprisals are recorded precisely, and they are the reason the episode belongs in any account of abolition. One white civilian and one Black soldier were killed in the fighting. Fifty enslaved people died in battle; seventy were executed in the field; 144 were tried and executed in Bridgetown; 132 were deported. Martial law ran from 15 April to 12 July, though the rising itself was suppressed within three days.

That ratio — two deaths on one side, nearly four hundred killed or deported on the other — is what colonial order looked like when it was threatened. The surviving evidence consists largely of letters from Governor James Leith and Colonel Edward Codd, plus a sketch of a captured flag: testimony from the side that did the executing, which is the ordinary condition of this archive and a reason to read it as our explainer on primary and secondary sources describes.

Rebellion of this kind, repeated across the Caribbean and Brazil, changed the calculation for planters and for metropolitan governments. It is not that revolt alone produced abolition; it is that an account of abolition without it is missing a cause.