Thomas Clarkson (28 March 1760 – 26 September 1846) was an English abolitionist, and a leading campaigner against the slave trade in the British Empire.

In 1840, he was the key speaker at the British and Foreign Anti-Slavery Society's first convention in London which campaigned to end slavery in other countries.

He received his Bachelor of Arts degree in 1783 and was set to continue at Cambridge to follow in his father's footsteps and enter the Anglican ministry.

The topic of the essay, set by university vice-chancellor Peter Peckard, was Anne liceat invitos in servitutem dare ("is it lawful to make slaves of others against their will?

He read everything he could on the subject, including the works of Anthony Benezet, a Quaker abolitionist, as well as first-hand accounts of the African slave trade such as Francis Moore's Travels Into the Inland Parts of Africa (1738).

The movement had been gathering strength for some years, having been founded by Quakers both in Britain and in the United States, with support from other nonconformists, primarily Methodists and Baptists, on both sides of the Atlantic.

Under the Test Act, only those prepared to receive the sacrament of the Lord's Supper according to the rites of the Church of England were permitted to serve as MPs, thus Quakers were generally barred from the House of Commons until the early nineteenth century.

The twelve founding members included nine Quakers, and three pioneering Anglicans: Clarkson, Granville Sharp, and Philip Sansom.

They were sympathetic to the religious revival that had predominantly nonconformist origins, but which sought wider non-denominational support for a "Great Awakening" amongst believers.

Wilberforce was one of few parliamentarians to have had sympathy with the Quaker petition; he had already put a question about the slave trade before the House of Commons, and became known as one of the earliest Anglican abolitionists.

The slave traders were an influential group because the trade was a legitimate and highly lucrative business, generating prosperity for many of the ports.

That same year, Clarkson published the pamphlet A Summary View of the Slave Trade and of the Probable Consequences of Its Abolition.

Clarkson was very effective at giving the committee a high public profile: he spent the next two years travelling around England, promoting the cause and gathering evidence.

Although not a slave ship, it carried cargo of high-quality goods: carved ivory and woven textiles, beeswax, and produce such as palm oil and peppers.

Demonstrating that Africans were highly skilled artisans, he argued for an alternative humane trading system based on goods rather than labourers.

As an African with direct experience of the slave trade and slavery, Equiano was pleased that his book became highly influential in the anti-slavery movement.

As Wilberforce continued to bring the issue of the slave trade before Parliament, Clarkson travelled and wrote anti-slavery works.

Clarkson, Wilberforce and the other members of the Committee for the Abolition of the Slave Trade and their supporters, were responsible for generating and sustaining a national movement that mobilised public opinion as never before.

Henry Dundas, 1st Viscount Melville, who was the Secretary of State for War for prime minister William Pitt the Younger, instructed Sir Adam Williamson, the lieutenant-governor of Jamaica, to sign an agreement with representatives of the French colonists of Saint Domingue, later Haiti, that promised to restore the ancien regime, slavery and discrimination against mixed-race colonists, a move that drew criticism from abolitionists Wilberforce and Clarkson.

Clarkson directed his efforts toward enforcement and extending the campaign to the rest of Europe, as Spain and France continued a trade in their American colonies.

The United States also prohibited the international trade in 1807, and operated chiefly in the Caribbean to interdict illegal slave ships.

The conference was intended to build support for abolishing slavery worldwide and included delegates from France, the US, Haiti (established in 1804 as the first black republic in the Western Hemisphere) and Jamaica.

[23] In 1846, Clarkson was host to Frederick Douglass, an American former slave who had escaped to freedom in the North and became a prominent abolitionist, on his first visit to England.

At risk even prior to passage in the US of the Fugitive Slave Law of 1850, Douglass was grateful when British friends raised the money and negotiated purchase of his freedom from his former master[25] in December 1846.

Throughout his life Clarkson was a frequent guest of Joseph Hardcastle (the first treasurer of the London Missionary Society) at Hatcham House in Deptford, then a Surrey village.

[citation needed] His younger brother John Clarkson (1764–1828) took a major part in organising the relocation of approximately 1200 Black Loyalists to Africa in early 1792.

They were among the 3000 former United States slaves given their freedom by the British and granted land in Nova Scotia, Canada, after the American Revolutionary War.