Brookes Slave Ship Diagram (1788): The Image That Shocked Britain

The Brookes slave ship diagram is a print first published in 1788 that shows hundreds of enslaved Africans packed into the decks of the Liverpool slave ship Brookes. Created by abolitionists in Plymouth and London, it turned measurements of a real ship into a stark visual argument against the Atlantic slave trade. It became the most famous image of the British abolition campaign and is still one of the most reproduced pictures of the Middle Passage.

Background: a campaign in search of evidence

In 1787 the Society for Effecting the Abolition of the Slave Trade began a national campaign against Britain’s slave trade. Its members knew that most Britons had never seen a slave ship. The trade took place far away, on the coasts of Africa and in the Caribbean, and its defenders insisted that the voyage across the Atlantic was healthy and humane.

Abolitionists therefore searched for evidence the public could not easily ignore. Thomas Clarkson collected testimony from sailors, ships’ surgeons and officials in Bristol and Liverpool. In 1788 Parliament began to examine the trade, and the government sent a naval officer, Captain Parrey, to Liverpool to measure slave ships. His figures for the Brookes provided the raw material for the diagram.

The ship Brookes

The Brookes was a Liverpool slave ship named after its owner, the merchant Joseph Brooks. Built in 1781, it made a series of voyages between Liverpool, West Africa and the Caribbean. Its lower deck was about 100 feet long and about 25 feet wide, and it was registered at around 300 tons.

On at least one voyage in the 1780s the Brookes carried more than 600 enslaved Africans, according to records later cited by abolitionists. That was before Dolben’s Act of 1788, the first British law to regulate the trade, limited the number of captives a ship could carry according to its tonnage.

Plymouth and London versions

The first version of the image was produced in late 1788 by the Plymouth committee of the abolition movement, chaired by William Elford. It showed the lower deck of the ship with figures arranged in rows, under the title Plan of an African Ship’s Lower Deck with Negroes in the Proportion of Only One to a Ton, and was printed as a broadside, a single large sheet for public display.

The London committee, working closely with Clarkson, then produced a more detailed version known as Description of a Slave Ship. Printed by the Quaker James Phillips, it added a longitudinal section, cross-sections and several decks, and included a dense explanatory text. Thousands of copies were printed in 1788–1789 and distributed through local committees, newspapers and magazines.

The number of figures differs between editions. Counts of 454 and 482 are both commonly cited for the London versions. The accompanying text made a key point: even under the new legal limits, people had to lie in spaces barely larger than a coffin, and on earlier voyages the ship had carried far more.

Why the image worked

The diagram’s power lay in its restrained, technical style. It looked like a naval architect’s drawing rather than a painting, and it was based on official measurements, which made it hard for supporters of the trade to dismiss it as exaggeration.

By drawing human beings in the same neat rows as cargo, it made visible the logic of the Middle Passage, in which people were treated as goods to be stowed. Viewers were left to imagine the heat, disease and suffering, and the human toll the plan implied.

The defenders of the trade, including Liverpool merchants and West India planters, argued that ships were clean, that captives were well fed and exercised on deck, and that losses at sea were small. Some witnesses for the trade told parliamentary inquiries that captives were content on board, singing and dancing on deck, claims that abolitionists answered by pointing out that the “dancing” was forced exercise under the whip. Against such testimony, the plan offered a measurable picture that anyone could check.

What the diagram leaves out

The diagram shows only one moment: people lying still in their allotted spaces. It does not show the chains, the sickness that spread in the hot, airless decks, the forced feeding of those who refused food, or the violence used to prevent revolts. Accounts by former ship surgeons such as Alexander Falconbridge, published in 1788, described decks so foul with blood and mucus that they resembled a slaughterhouse, and abolitionists printed such accounts alongside the image.

The London version did divide the decks into separate areas for men, women, boys and girls, reflecting real shipboard practice, but the figures are uniform and expressionless. Men were usually shackled in pairs, a detail most versions show only faintly, and nothing in the plan conveys the length of a voyage that could last two months or more.

Spread and influence

The image travelled quickly. Abolitionists in the United States, including Mathew Carey in Philadelphia, published versions in 1789, and the Société des Amis des Noirs produced a French version. The French revolutionary politician Mirabeau reportedly had a wooden model of the ship made to support his own arguments against the trade.

In Britain, campaigners used the image in pamphlets and at public meetings, and William Wilberforce drew on the same evidence in his first great speech against the trade in May 1789. Clarkson included a large folding version in his 1808 history of the abolition campaign, which kept the image in circulation after the trade was abolished in 1807.

Criticism and legacy

Modern historians, including Marcus Rediker and Marcus Wood, have studied the diagram closely. They note that it presents Africans as anonymous, passive and identical figures, leaving out the resistance, revolts and individual lives recorded in other sources. It also reflects the abolitionists’ strategy of appealing to British sympathy rather than to African voices.

Others point out that the diagram served a specific political purpose. By stressing overcrowding, it implied that the trade might be reformed through better regulation, a reading that supporters of Dolben’s Act could accept. Abolitionists had to work hard to argue that the problem was the trade itself, not just the number of people on each ship.

Even so, the Brookes print has remained central to how the slave trade is remembered. It was widely used during the 2007 bicentenary of British abolition, appears in museums and textbooks around the world, and has inspired many modern artists who reuse its rows of figures to address slavery and its legacy.

Timeline

• 1781: The Brookes is built in Liverpool.
• 1787, May: The Society for Effecting the Abolition of the Slave Trade is founded in London.
• 1788: Captain Parrey measures Liverpool slave ships, including the Brookes.
• 1788, July: Dolben’s Act limits the number of captives per ship by tonnage.
• 1788, late: The Plymouth committee publishes its plan of the ship’s lower deck.
• 1788–1789: The London committee publishes Description of a Slave Ship, printed by James Phillips.
• 1789, 12 May: Wilberforce’s first major Commons speech against the trade.
• 1789: Versions of the image appear in the United States and France.
• 1808: Clarkson reproduces the diagram in his history of the abolition campaign.

Why it matters

The Brookes diagram showed how a single, carefully designed image could change public opinion. It brought the hidden reality of the slave ship into British homes and coffee houses, helped build support for abolition and remains a defining visual record of the Atlantic slave trade.