A sustained campaign by abolitionists.

Various groups of Quakers, Methodists and Baptists, as well as notable individuals such as Granville Sharp, had pushed the abolitionist cause as early as the 1760s but the movement coalesces around the Society for Effecting the Abolition of the Slave Trade, established in 1787. Thomas Clarkson was a leading figure in this Society, he then recruited the MP William Wilberforce, who would come to lead the campaign from within the Parliament. Writers such as Hannah More and Mary Birkett published poems and other works aimed at swaying popular opinion. John Newton (writer of the hymn Amazing Grace), who had worked on a slaver ship as a young man before renouncing slavery later in life, was a friend of Wilberforce and also a supporter of the abolitionist cause. The lawyer James Stephen had a significant role in drafting what would ultimately become the legislation abolishing the trade.

The movement also drew support from former slaves such as Olaudah Equiano, who published a widely-distributed account of his experiences as a slave in 1789, and Ottobah Cugoano, who published a book attacking slavery in 1787. Both were members of the black abolitionist society, the Sons of Africa.

After the passage of the Slave Trade Act in 1807 the same organisations would go on to lead the campaign to abolish slavery within the Empire altogether, achieved with the Slavery Abolition Act 1833.

Most histories have focused attention on the influence of Christian, and particularly evangelical thought on this movement (though today in the sense of identifying religion as a motivating factor, as opposed to the "they won because they had faith" approaches of the 19th century), however more modern approaches have similarly recognised the influence of Enlightenment humanist thought and the role of secular organisations within the broader abolitionist camp.

A number of approaches advanced in the middle of the 20th century argued that economic factors (namely a supposed decline in the plantation economy from the 1760s, spurred by the rise of industrial Adam-Smith-ish free trade) precipitated the abolition of the trade, but these theories have not been borne out by the available economic data, and thus have fallen out of favour.