anti-slavery. Slavery was regarded in later 18th-cent. Britain as essential to the exploitation of the West Indian colonies where, it was believed, only negroes were capable of working on the sugar plantations. As those colonies were thought to be the keystone of imperial prosperity there was strong opposition to any interference with the institution, particularly from centres like Bristol and Liverpool whose economies depended on the plantations or on the Atlantic slave trade which supplied them.

The moral objections to slavery arose mainly from the evangelical movement of the second half of the century, reflecting concern for the spiritual and physical welfare of all mankind. A national committee of nine quakers and three Anglicans was set up in London in 1787, headed by Granville Sharp with Thomas Clarkson as secretary. It was decided to aim first at the suppression of the slave trade, whose cruelty was the subject of widespread propaganda. In 1788 William Wilberforce, the son of a Hull merchant, joined the cause after his evangelical conversion, and supplied parliamentary leadership. He persuaded his friend William Pitt to give it unofficial backing and committees were set up in provincial towns, the most active being in Manchester. Over a hundred petitions were submitted in support of Wilberforce's parliamentary motion to end the trade in 1789. However, the economic arguments in favour of the trade prevailed, and after another unsuccessful attempt in 1791, the abolitionist cause suffered from the reaction against the French Revolution. The agitation was revived by Clarkson's speaking tours in 1804, by which time the economic importance of the West Indies had lessened, and in 1807 Lord Grenville, an early convert, gave his government's backing to an abolition bill, forcing it through the Lords.

The campaign to abolish slavery itself throughout the British empire began in earnest in 1823, when the Anti-Slavery Society was formed in London by evangelicals, quakers, and methodists. The leaders included James Cropper, a quaker merchant from Liverpool, Joseph Sturge, a Birmingham corn merchant, and in Parliament Henry Brougham, T. F. Buxton, T. B. Macaulay, and Wilberforce. A campaign during the 1830 general election encouraged Grey's government to put through a bill abolishing slavery in the British empire in 1833, substituting apprenticeship for seven years. This vestige of slavery was abolished from 1 August 1838. The movements against slavery and the slave trade marked an important stage in the development of middle-class pressure groups both in London and in the industrial provinces. See also slave trade.

E. A. Smith