The Committee for the Abolition of the Slave Trade was formed in 1787 by a group of Evangelical English Protestants allied with Quakers, to unite in their shared opposition to slavery and the slave trade. The Quakers had long viewed slavery as immoral, a blight upon humanity. By 1807 the abolitionist groups had a very sizable faction of like-minded members in the British Parliament. At their height they controlled 35–40 seats. Known as the "Saints", the alliance was led by the best known of the anti-slave trade campaigners, William Wilberforce, who had taken on the cause of abolition in 1787 after having read the evidence that Thomas Clarkson had amassed against the trade. These dedicated Parliamentarians had access to the legal draughtsmanship of James Stephen, Wilberforce's brother-in-law. They often saw their personal battle against slavery as a divinely ordained crusade. On Sunday, 28 October 1787, Wilberforce wrote in his diary: "God Almighty has set before me two great objects, the suppression of the slave trade and the reformation of manners."
Their numbers were magnified by the precarious position of the government under Lord Grenville, whose short term as Prime Minister was known as the Ministry of All the Talents. Grenville himself led the fight to pass the bill in the House of Lords, while in the Commons the Bill was led by the Foreign Secretary, Lord Howick (Charles Grey, later Earl Grey). Other events also played a part; the Acts of Union 1800 brought 100 Irish MPs into Parliament, most of whom supported abolition. The Bill was first introduced to Parliament in January 1807. It went to the House of Commons on 10 February 1807. On 23 February 1807, twenty years after he first began his crusade, Wilberforce and his team were rewarded with victory. After a debate lasting ten hours, the House agreed to the second reading of the bill to abolish the Atlantic slave trade by an overwhelming 283 votes for to 16. The Bill received Royal Assent on 25 March 1807.