The Slavery Abolition Act 1833 (3 & 4 Will. IV c. 73) abolished slavery throughout the British Empire. This Act of the Parliament of the United Kingdom, expanded the jurisdiction of the Slave Trade Act 1807, making the purchase or ownership of slaves illegal within the British Empire, with the exception "of the Territories in the Possession of the East India Company", Ceylon (now Sri Lanka), and Saint Helena. The Act was repealed in 1998 as a part of wider rationalisation of English statute law; however, later anti-slavery legislation remains in force.
In May 1772, Lord Mansfield's judgement in the Somersett's Case emancipated a slave in England, which helped launch the movement to abolish slavery. The case ruled that slavery was unsupported by law in England and no authority could be exercised on slaves entering English or Scottish soil. In 1785, English poet William Cowper wrote:
We have no slaves at home – Then why abroad?
Slaves cannot breathe in England; if their lungs
Receive our air, that moment they are free.
They touch our country, and their shackles fall.
That's noble, and bespeaks a nation proud.
And jealous of the blessing. Spread it then,
And let it circulate through every vein.
By 1783, an anti-slavery movement to abolish the slave trade throughout the Empire had begun among the British public. In 1793 Lieutenant-Governor of Upper Canada John Graves Simcoe signed the Act Against Slavery. Passed by the local Legislative Assembly, it was the first legislation to outlaw the slave trade in a part of the British Empire.
In 1807, Parliament passed the Slave Trade Act of 1807, which outlawed the slave trade, but not slavery itself. Abolitionist Henry Brougham realized that trading would continue and as an new MP successfully introduced the Slave Trade Felony Act 1811 which at last made slave trading criminal throughout the empire. The Royal Navy established the West Africa Squadron to suppress the Atlantic slave trade by patrolling the coast of West Africa. It did suppress the slave trade, but did not stop it entirely. Between 1808 and 1860, the West Africa Squadron captured 1,600 slave ships and freed 150,000 Africans. They resettled many in Jamaica and the Bahamas. Britain also used its influence to coerce other countries to agree treaties to end their slave trade and allow the Royal Navy to seize their slave ships.
In 1823, the Anti-Slavery Society was founded in London. Members included Joseph Sturge, Thomas Clarkson, William Wilberforce, Henry Brougham, Thomas Fowell Buxton, Elizabeth Heyrick, Mary Lloyd, Jane Smeal, Elizabeth Pease, and Anne Knight. William Wilberforce had prior written in his diary in 1787 that his great purpose in life was to suppress the slave trade before waging a 20-year fight on the industry.
During the Christmas holiday of 1831, a large-scale slave revolt in Jamaica, known as the Baptist War, broke out. It was organised originally as a peaceful strike by the Baptist minister Samuel Sharpe. The rebellion was suppressed by the militia of the Jamaican plantocracy and the British garrison ten days later in early 1832. Because of the loss of property and life in the 1831 rebellion, the British Parliament held two inquiries. The results of these inquiries contributed greatly to the abolition of slavery with the Slavery Abolition Act 1833.
The Act had its third reading in the House of Commons on 26 July 1833, three days before William Wilberforce died. It received the Royal Assent a month later, on 28 August, and came into force the following year, on 1 August 1834. In practical terms, only slaves below the age of six were freed in the colonies. Former slaves over the age of six were redesignated as "apprentices", and their servitude was abolished in two stages: the first set of apprenticeships came to an end on 1 August 1838, while the final apprenticeships were scheduled to cease on 1 August 1840. The Act specifically excluded "the Territories in the Possession of the East India Company, or to the Island of Ceylon, or to the Island of Saint Helena." The exceptions were eliminated in 1843.
The Act provided for compensation for slave-owners. The amount of money to be spent on the compensation claims was set at "the Sum of Twenty Million Pounds Sterling". Under the terms of the Act, the British government raised £20 million (£16.5 billion in 2013 pounds, when calculated as wage values) to pay out in compensation for the loss of the slaves as business assets to the registered owners of the freed slaves. In 1833, £20 million amounted to 40% of the Treasury's annual income or approximately 5% of the British GDP (5% of the British GDP in 2016 was around £100 billion). To finance the compensation, the British government had to take on a £15 million loan, finalised on 3 August 1835, with banker Nathan Mayer Rothschild and his brother-in-law Moses Montefiore. The money wasn't paid back until 2015.
Half of the money went to slave-owning families in the Caribbean and Africa, while the other half went to absentee owners living in Britain. The names listed in the returns for slave compensation show that ownership was spread over many hundreds of British families, many of them of high social standing. For example, Henry Phillpotts (then the Bishop of Exeter), with three others (as trustees and executors of the will of John Ward, 1st Earl of Dudley), was paid £12,700 for 665 slaves in the West Indies, whilst Henry Lascelles, 2nd Earl of Harewood received £26,309 for 2,554 slaves on 6 plantations. The majority of men and women who were awarded compensation under the 1833 Abolition Act are listed in a Parliamentary Return, entitled Slavery Abolition Act, which is an account of all moneys awarded by the Commissioners of Slave Compensation in the Parliamentary Papers 1837-8 (215) vol. 48.
On 1 August 1834, an unarmed group of mainly elderly people being addressed by the Governor at Government House in Port of Spain, Trinidad, about the new laws, began chanting: "Pas de six ans. Point de six ans" ("Not six years. No six years"), drowning out the voice of the Governor. Peaceful protests continued until a resolution to abolish apprenticeship was passed and de facto freedom was achieved. Full emancipation for all was legally granted ahead of schedule on 1 August 1838.
As a notable exception to the rest of the British Empire, the Act did not "extend to any of the Territories in the Possession of the East India Company, or to the Island of Ceylon, or to the Island of Saint Helena." Slavery was abolished in India by the Indian Slavery Act of 1843.
A successor organisation to the Anti-Slavery Society was formed in London in 1839, the British and Foreign Anti-Slavery Society, which worked to outlaw slavery worldwide. The world's oldest international human rights organisation, it continues today as Anti-Slavery International.
It is believed that after 1833 clandestine slave-trading continued within the British Empire; in 1854 Nathaniel Isaacs, owner of the island of Matakong off the coast of Sierra Leone was accused of slave-trading by the governor of Sierra Leone, Sir Arthur Kennedy. Papers relating to the charges were lost when the Forerunner was wrecked off Madeira in October 1854. In the absence of the papers, the English courts refused to proceed with the prosecution.
The Slavery Abolition Act 1833 was repealed in its entirety by the Statute Law (Repeals) Act 1998. The repeal has not made slavery legal again, with sections of the Slave Trade Act 1824, Slave Trade Act 1843 and Slave Trade Act 1873 continuing in force. In its place the Human Rights Act 1998 incorporates into British Law Article 4 of the European Convention on Human Rights which prohibits the holding of persons as slaves.