Slavery Abolition Act 1833
Slavery had been abolished in England in 1772 by  and Britain had outlawed the slave trade with the Slave Trade Act in 1807, with penalties of £100 per slave levied on British captains found importing slaves (treaties signed with other nations expanded the scope of the trading ban). Small trading nations that did not have a great deal to give up, such as Sweden, quickly followed suit, as did the Netherlands, also by then a minor player, however the British empire on its own constituted a substantial fraction of the world’s population. The Royal Navy established the West Africa Squadron (or Preventative Squadron) at substantial expense in 1808 after Parliament passed the Act. The squadron’s task was to suppress the Atlantic slave trade by patrolling the coast of West Africa. This suppressed the slave trade but did not stop it entirely. It is possible that if slave ships were in danger of being captured by the Royal Navy, some captains may have ordered the slaves to be thrown into the sea to reduce the fines they had to pay. Between 1808 and 1860 the West Africa Squadron captured 1,600 slave ships and freed 150,000 Africans.  . Notwithstanding what had been done to suppress the trade, further measures were soon discovered to be necessary.
The first Society for Effecting the Abolition of the Slave Trade was established in Britain in 1787, and members included John Barton; William Dillwyn; George Harrison; Samuel Hoare Jr; Joseph Hooper; John Lloyd; Joseph Woods Sr; James Phillips; Thomas Clarkson, Granville Sharp, Philip Sansom and Richard Phillips. 
The later Anti-Slavery Society was founded in 1823. Members included Joseph Sturge, Thomas Clarkson, William Wilberforce, Henry Brougham, Thomas Fowell Buxton, Elizabeth Heyrick, Mary Lloyd, Jane Smeal, Elizabeth Pease and Anne Knight. 
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 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 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.
A successor organisation to the Anti-Slavery Society was formed in 1839, committed to worldwide abolition. Its official name was the British and Foreign Anti-Slavery Society.  This continues today as Anti-Slavery International.
Main points of the Act
Slavery was officially abolished in most of the British Empire on 1 August 1834. In practical terms, however, only slaves below the age of six were freed, as all slaves over the age of six were redesignated as “apprentices”. Apprentices would continue to serve their former owners for a period of time after the abolition of slavery, though the length of time they served depended on which of three classes of apprentice they were.
The first class of apprentices were former slaves who “in their State of Slavery were usually employed in Agriculture, or in the Manufacture of Colonial Produce or otherwise, upon Lands belonging to their Owners”. The second class of apprentices were former slaves who “in their State of Slavery were usually employed in Agriculture, or in the Manufacture of Colonial Produce or otherwise, upon Lands not belonging to their Owners”. The third class of apprentices was composed of all former slaves “not included within either of the Two preceding Classes”. Apprentices within the third class were released from their apprenticeships on 1 August 1838. The remaining apprentices within the first and second classes were released from their apprenticeships on 1 August 1840.
The Act also included the right of compensation for slave-owners who would be losing their property. The amount of money to be spent on the compensation claims was set at “the Sum of Twenty Millions Pounds Sterling”. Under the terms of the Act the British government raised £20 million to pay out in compensation for the loss of the slaves as business assets to the registered owners of the freed slaves. 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), in a partnership with three business colleagues, received £12,700 for 665 slaves. 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 Vol. 48.
In all, the government paid out over 40,000 separate awards. The £20 million fund was 40% of the government’s total annual expenditure.
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.”
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, making Trinidad the first British colony with slaves to completely abolish slavery.
The Slavery Abolition Act 1833 was repealed in its entirety under the Statute Law (Repeals) Act 1998.   However, this repeal has not made slavery legal again, as sections of the Slave Trade Act 1824, Slave Trade Act 1843 and Slave Trade Act 1873 are still in force. In addition 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.