It was part of a wider abolitionism movement in Western Europe and the Americas. Soon after his death in 1785, they joined with William Wilberforce, though anti-slavery sentiment was widespread by the late 18th century, the colonies and emerging nation-states that used slave labour continued to do so. The slave trade had been banned in England in 1102, in a 1569 court case involving Cartwright, who had bought a slave from Russia, the court ruled that English law could not recognise slavery, as it was never established officially. This ruling was overshadowed by later developments and it was upheld in 1700 by Lord Chief Justice Sir John Holt when he ruled that a slave became free as soon as he arrived in England. English colonists imported slaves to the North American colonies and by the 18th century, traders began to import slaves from Africa, India and East Asia to London and Edinburgh to work as servants. Men who migrated to the North American colonies often took their East Indian slaves or servants with them, some of the first freedom suits, court cases in Britain to challenge the legality of slavery, took place in Scotland in 1755 and 1769. The cases were Montgomery v. Sheddan and Spens v. Dalrymple, each of the slaves had been baptised in Scotland and challenged the legality of slavery. They set the precedent of legal procedure in British courts that would lead to success for the plaintiffs. In these cases, deaths of the plaintiff and defendant, respectively, African slaves were not bought or sold in London itself but were brought by masters from other places. Together with people from nations, especially non-Christian ones, Africans were considered foreigners. At the time, England had no naturalisation procedure, the African slaves legal status was unclear until the 1772 Somersetts Case, when the fugitive slave James Somersett forced a decision by the courts. Somersett had escaped and his master, Charles Steuart, had him captured and imprisoned on board a ship, while in London, Somersett had been baptised and three godparents issued a writ of habeas corpus. As a result, Lord Mansfield, Chief Justice of the Court of the Kings Bench, had to judge whether Somersetts abduction was lawful or not under English Common Law, no legislation had ever been passed to establish slavery in England. The case received national attention and five supported the action on behalf of Somersett. It is so odious, that nothing can be suffered to support it, whatever inconveniences, therefore, may follow from a decision, I cannot say this case is allowed or approved by the law of England, and therefore the black must be discharged. The decision did not apply to British overseas territories, e. g. the American colonies had established slavery by positive laws, Somersetts case became a significant part of the common law of slavery in the English-speaking world and it helped launch the movement to abolish slavery. After reading about Somersetts Case, Joseph Knight, an enslaved African who had purchased by his master John Wedderburn in Jamaica and brought to Scotland. Married and with a child, he filed a freedom suit, in the case of Knight v. Wedderburn, Wedderburn said that Knight owed him perpetual servitude
Lord Mansfield (1705–1793), whose opinion in Somerset's Case (1772) was widely taken to have held that there was no basis in law for slavery in England.
Ignatius Sancho (c1729–1780) gained fame in his time as "the extraordinary Negro". To 18th-century British abolitionists, he became a symbol of the humanity of Africans and the immorality of the slave trade.
William Wilberforce (1759–1833), politician and philanthropist who was a leader of the movement to abolish the slave trade.
Blake's "A Negro Hung Alive by the Ribs to a Gallows", an illustration to J. G. Stedman's Narrative, of a Five Years' Expedition, against the Revolted Negroes of Surinam (1796).