Quakers, who believed slavery was sinful, followed William Wilberforce, who claimed it was against the Christian teachings. Quakers worked together collecting information about terrible condition for the slaves, on the slave ships, from their owners used to persuade people to sign petitions which were presented to parliament and in 1807 they were successful.
Others depicted conditions and some used the argument that like us they are human beings and they should be treated like us.
The ordinary working-class were now signing petitions for slave abolishment, in 1814, 1.5 million signed, support was growing and no-one could stop it. People believed everyone should have rights and that slavery was wrong. The government were also scared of strikes and people getting in groups so they usually gave into the petitions if this was what so many want.
Black slaves also took action, demanding to be treated better and to have wages like an ordinary servant. Many others simply ran away and owners tried to get them back using the courts but the legal position was never really clear on slavery. Olaudah Equiano, was forced into slavery but learnt how to read and write, and in 1789 wrote a book of his life which many people read and changed their view on slavery and put many against it, he traveled and spoke at meetings, bringing to attention of the public, recent cases against human rights such as the slave ship Zong.
In 1789 at St. Domingue a French colony, France planned an alliance with Britain, the slave knew this would mean slavery would continue and their conditions were among the worst so in 1791 the slaves rebelled, defeated the English as well as the French.
Economic also played a part in the process; the West Indies were becoming less important, with Cuba and Brazil producing sugar more cheaply. Plantations were closed, in 1772 no slaves were imported and the demand for slaves had fallen. Economist Adam Smith wrote that slaves have nothing, so labour as little as possible, ‘Whatever work he does can be squeezed out of him by violence only.’
When slaves in Jamaica in 1831 went on strike, setting fires to cane fields many were shot and more were hung, After this people realized that conditions would never simply improve and in 1833 slavery was finally abolished.
As you can see there are a range of factors that contributed to the abolishment of slavery, truth was that was no law on slavery before it was abolished, it was down to pressure from petitions, people’s actions and economy that forced the government to make slavery illegal, giving many rights, stopping the revolts and making everyone equal.