At the end of the 18th century, public opinion began to turn against the slave trade.
The Society of Friends (a Christian group also known as the Quakers) opposed the slave trade. In 1761 they decided none of their members could be involved in trading slaves.
In 1787, the Society for the Abolition of the Slave Trade was set up. William Wilberforce MP represented the Society in Parliament.
The Society for the Abolition of the Slave Trade decided that the best approach was to try to end the slave trade rather than slavery itself.
It would make slave masters treat their slaves better, as there would be less of them.