47 Geo 3 Sess 1 c 36, sometimes called the Slave Trade Act, the Slave Trade Act 1807 or the Abolition of the Slave Trade Act 1807, was an Act of the Parliament of the United Kingdom passed on 25 March 1807, with the title of “An Act for the Abolition of the Slave Trade”. The original act is in the Parliamentary Archives. The act abolished the slave trade in the British Empire, in particular the Atlantic slave trade, and also encouraged British action to press other European states to abolish their slave trades, but it did not abolish slavery itself. Many of the Bill’s supporters thought the Act would lead to the death of slavery, but it was not until 26 years later that slavery itself was actually abolished. Slavery on English soil was unsupported in English law and that position was confirmed in Somersett’s Case in 1772, but it remained legal in most of the British Empire until the Slavery Abolition Act 1833.
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, Charles James Fox, who died before it finally received Royal Assent. Other events also played a part; the Act of Union 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. By an overwhelming 283 votes for to 16 against, the motion to abolish the Atlantic slave trade was carried in the House of Commons. The debate lasted ten hours and the House voted in favour of the Bill. The Bill received Royal Assent on 25 March 1807.
The Act created fines for captains who continued with the trade. These fines could be up to £100 per slave found on a ship. Captains would sometimes dump slaves overboard when they saw Navy ships coming in order to avoid these fines.
The Royal Navy, which then controlled the world’s seas, established the West Africa Squadron in 1808 to patrol the coast of West Africa, and between 1808 and 1860 they seized approximately 1,600 slave ships and freed 150,000 Africans who were aboard. The Royal Navy declared that ships transporting slaves were the same as pirates. Action was also taken against African leaders who refused to agree to British treaties to outlaw the trade, for example against “the usurping King of Lagos”, who was deposed in 1851. Anti-slavery treaties were signed with over 50 African rulers.