A haunting sketch of a ship captain assaulting a teenage slave girl who later died was a major driving force behind the abolitionist movement, experts have revealed.

Captain John Kimber was accused of suspending the 15-year-old child by her ankle while whipping her on deck with a cat o’ nine tails, before she died five days later.

The punishment on the merchant ship Recovery travelling from modern-day Nigeria to Grenada in 1791 generated huge public interest in the UK when it was revealed.

In the House of Commons the following year, famed abolitionist William Wilberforce accused Kimber of killing the girl and the captain was tried for murder but acquitted.

Kimber later demanded compensation and an apology – but Wilberforce and his allies claimed the trial was poorly handled and it gained significant attention in the British press, also establishing that anyone who killed a slave could be tried for murder.

The incident was immortalised in a striking print by Scottish painter Isaac Cruikshank which he produced just eight days after Wilberforce’s initial statement to Parliament.

Now, a Royal Museums Greenwich team has explained how the notorious case was a key moment in the movement leading to the 1807 Abolition of the Slave Trade Act.

A spokeswoman for the museum, whose curators have researched the case and the wider slave trade, told the Daily Mail: ‘The significance of the sketch lies in its role as a piece of powerful, immediate, and widely distributed visual propaganda that directly influenced public opinion during a critical moment in the British abolition movement.

‘Cruikshank’s print was published just eight days after Wilberforce’s speech. This rapid deployment of the image ensured that the public received a visceral, emotional representation of the testimony while the political debate was at its peak.

A print by Scottish painter Isaac Cruikshank shows John Kimber (left) suspending a slave girl by her ankle while whipping her with a cat o’ nine tails on board the Recovery ship in 1791

‘As a relatively inexpensive medium, prints could be mass-produced and widely circulated in public spaces, coffee houses, and private homes.

‘It allowed the abolitionist message to reach a broad cross-section of society, including those who could not read the pamphlets or parliamentary reports. 

‘It was a deliberate piece of political campaigning, designed to pressure Members of Parliament by demonstrating the strength and moral conviction of the public.’

Wilberforce first learned of the incident while initially investigating an outrage at New Calabar in the Niger Delta, where Kimber’s ship had travelled from Bristol.

The captain found the locals in what is now Nigeria would not give him slaves or water, so began a bombardment of the town to try to force down the price of slaves.

This attack using cannons was successful and the Recovery took on board around 300 slaves to be sold in Grenada. Some 27 of them died during the two-month voyage.

The incident involving the alleged murder is said to have begun on September 22, 1791 after the girl had refused to take part in a ‘dancing the slaves’ routine, when the crew would force slaves to dance in an attempt to prevent them from dying from illness.

Slaves who did not take part in the dance were often flogged or raped – and Wilberforce claimed Kimber repeatedly lashed the girl and had her suspended by the ankle before being dropped to the deck multiple times.

The girl is thought to have been already been raped and inflicted with gonorrhoea after being enslaved, with blame for the disease’s spread put on the African women on board.

Kimber flogged her each day with whips and ropes as she refused to dance, before she became unable to walk properly. He is then claimed to have strung her up by her bad leg, then the other leg and then her arms – whipping her in each position.

The girl, whose name was never recorded, fell down the stairs into the hold and later died on September 27. The captain was quoted as saying: ‘The b**** is sulky.’

The sketch shows the girl being suspended by the ankle from a rope held over a pulley by a sailor, who leans back and says: ‘Dam me if I like it I have a good mind to let go’.

Two other sailors can be seen walking away, saying, ‘My Eyes Jack our Girles at Wapping are never flogged for their modesty,’ and: ‘By G-d that’s too bad if he had taken her to bed to him it would be well enough, Split me I’m allmost sick of this Black Business.’

Kimber meanwhile is standing with a grinning leer and his hands on his chest as if he is laughing, with a whip in his right hand and two further scourges on the deck.

Famed abolitionist William Wilberforce (as shown in the above drawing) spoke in the House of Commons in 1792 where he accused Kimber of killing the girl, which later led to a murder trial

Three naked adult women slaves can be seen in the background, with one putting her hands on her face. The lower part of a mast and sail on the ship can also be seen.

The print dated to April 10, 1792 also had a caption underneath, reading: ‘The abolition of the slave trade. Or the inhumanity of dealers in human flesh exemplified in Capt’n Kimber’s treatment of a young Negro girl of 15 for her virgin modesty.’

A second print was also produced with an amended sub-title with Kimber’s name erased and changed by hand to read ‘exemplified in the cruel treatment’.

This is thought to have been done after the trial to prevent any legal action by Kimber, particularly as the sexualised depiction of the girl was at odds with official evidence – meaning his remaining prints could be sold.

Wilberforce was told about the case by the ship’s surgeon Thomas Dowling, then raised it in the Commons during a debate on the slave trade on April 2, 1792.

In response of cries from all parts of the House of ‘Name!’, he gave that of Kimber – and the politician’s comments gained significant attention in the press.

Kimber then placed an advertisement in newspapers five days later on April 7 which denied the assault and promised to tell his own side of the story.

He was arrested in Bristol on April 8 and taken to London before going on trial at the Old Bailey on June 7 – which was attended by prominent politicians and seafarers of the day, including Lord Nelson.

Kimber was accused in court of assaulting the girl by suspending her by the ankle while beating her with a whip, and that she died of injuries because of the attack.

However the key witnesses against him, Dowling and Third Mate Stephen Devereaux, were accused of making up the case because they had fallen out with him.

The trial lasted just five hours and featured a series of witnesses speaking in support of Kimber, who claimed the girl had in fact died of disease – before the judge directed the jury to find the captain not guilty.

The trial for Kimber was viewed as an important step given that African slaves on board ships were generally regarded as ‘cargo’. This was a fact argued in court for insurance purposes after the Zong massacre in 1781 (above) which saw more than 130 enslaved Africans killed

Judge Sir James Marriott is said to have told the court: ‘A ship is a little government in which there can be no hope of any security for any man without a rapid and strong occasional exertion of an absolute power, placed in one man.’

After Kimber had been honourably acquitted, both Dowling and Devereaux were tried for perjury – with the former found guilty then later pardoned.

But abolitionist campaigners were unconvinced by the outcome, with Wilberforce believing that the judge favoured Kimber and prosecution lawyers had performed poorly.

The criminal indictment was also viewed as an important step given that African slaves on board ships were generally regarded as ‘cargo’.

This was a fact argued in court for insurance purposes after the Zong massacre in 1781 which saw more than 130 enslaved Africans killed by a British slave ship crew.

As for Kimber, he attempted to sue Wilberforce for damages after his acquittal before stalking him outside his home – but he eventually returned to the slave trade.

The museum spokeswoman said: ‘Enslaved Africans had been resisting enslavement and pursuing freedom since the beginning of the transatlantic trade and, by the late 18th century, there was a well-developed abolition movement in Britain.

‘The Cruikshank print and Captain Kimber’s trial were critically important in advancing abolition, particularly the parliamentary campaign to abolish the slave trade.

‘Their importance can be understood through their combined effect on British public opinion and political action. While the Zong Massacre is better remembered today, and was seen as significant by abolitionists at the time, Kimber’s case generated more contemporary media coverage.

‘The image was designed to generate immediate and profound moral outrage. The trial of Captain John Kimber for the murder of the enslaved girl, which occurred shortly after the sketch’s publication, was equally important, though its impact was paradoxical.’

She said that while Kimber was ultimately acquitted, this strengthened rather than weakened the abolitionist cause, because they ‘argued that the acquittal proved that the slave trade was so inherently corrupt and protected by the law that it was impossible to prosecute its worst abuses’.

The spokeswoman added: ‘This failure of justice became a powerful argument for the necessity of abolishing the entire system, not just regulating it. The entire episode—Wilberforce’s speech, the sketch, and the trial—occurred in 1792, a year of intense parliamentary debate.

‘The public outcry fuelled by the sketch and the trial contributed to the House of Commons passing a resolution for the ‘gradual’ abolition of the slave trade in that same year. Although the House of Lords later blocked the measure, the 1792 resolution was the first time the Commons had voted for abolition, marking a significant advance.’

The topic of the slave trade was back in the news in October when Sir Lenny Henry claimed all black Britons should be paid slavery reparations and suggested a ‘Robin Hood tax’ on financial transactions could fund it.

The comedian argued in a book that the UK should hand over an unspecified amount of money to its black population because of the ‘effects of slavery’.

He justified this by saying the reasons for modern-day racism and institutionalised racism in police forces can be traced back to the transatlantic slave trade.