Led by William Wilberforce, the abolitionists spent two decades trying to get Parliament to pass a law ending the slave trade.
In 1789, Wilberforce gave a three hour speech against slavery in Parliament. In 1791, Wilberforce presented to the House of Commons another Bill to abolish the slave trade.
He had the support of Prime Minister William Pitt the Younger, but the Bill was not passed. It was rejected by 163 votes to 88.
In every year between 1789 and 1806, Wilberforce presented a Bill for the abolition of the slave trade. In 1804, the House of Commons voted in favour of abolition, but Wilberforce’s Bill was rejected by the House of Lords.
In 1806, Wilberforce’s friend James Stephen proposed a Bill banning British ships from carrying enslaved people to French colonies. Pro-slavery MPs didn't see the significance of the Bill and let it pass. This stopped two-thirds of the slave trade and made it unprofitable.
In 1807, after a huge campaign, Parliament abolished the slave trade.