There is debate among historians over which factors were the most important in bringing about the end of the transatlantic slave trade. These included a number of factors.
The level of popular support for abolition across Britain during the 1790s, clearly shows that public opinion had swung in favour of the abolitionist cause and the banning of the slave trade.
Petitions to Parliament and the boycott of West Indian sugar attracted hundreds of thousands of supporters. A revival of interest in religion during the late 18th century made people think about the moral wrongs of the slave trade.
There is some evidence that the slave trade was becoming less profitable. The price of buying slaves in Africa was rising, reaching £25 in 1800. However, the price for selling in the Americas had not risen as quickly and was only £35 in the same year.
Historian Eric Williams showed that the slave trade hadn't been making as much money in the years shortly before abolition. He argued this was the reason that it was abolished. With the growth of trade to the Far East and India, Britain no longer needed the slave trade.
Much of the credit for the success of the abolitionist campaign must go to William Wilberforce for making the abolition of slavery an issue for debate in Parliament. His ability as a speaker persuaded many others of the need to end the trade.
Historians have also shown the importance of James Stephen's bill of 1806. In effect, Parliament only abolished the slave trade when it had virtually collapsed anyway.