Prime Minister Tony Blair has voiced his "deep sorrow" over Britain's role in the slave trade on Monday - a trade that helped Britain become one of the world's greatest powers in the 17th and 18th centuries.
Slavery had been illegal in Britain since 1102, but there were no laws to stop the use of slaves to toil in the fields and plantations of the growing empire.
Soon after the discovery of North America and the setting up of British colonies, the native population had been decimated by disease. The Crown began the wholesale transportation of African slaves to work in the colonies.
Slaves in the British colonies in the Caribbean worked on the sugar plantations which helped make the empire rich.
During the course of the 18th century the British perfected the Atlantic slave system. It is thought between 1700 and 1810 British merchants transported almost three million Africans across the Atlantic. More than 30,000 slave voyages took place.
Some historians have argued that the transatlantic slave trade created the bedrock for the modern capitalist system, creating immense wealth for the British companies which ran it.
Cities such as Bristol, London and Liverpool grew rich off the trade.
The slaves included not only Africans but men arrested after a Royalist uprising in the West Country in 1655, and Irish Catholics captured by Oliver Cromwell.
Much of Bristol's 18th Century wealth came from the slave trade
Slaves were transported in miserable conditions, crowded into cargo holds and with little access to fresh air, clean water or proper food. Many died on the way.
They worked in the sugar cane field, an industry which relied on intensive labour rather than industrialisation.
The slave traders chose Africans because they were used to working in hot conditions.
Other slaves were brought into service as personal servants in polite society in cities such as London and Edinburgh.
William Wilberforce was a leading anti-slavery exponent
Christian churches had turned a blind eye to the slave trade, but later helped lead the campaign to ban the use of slaves in British industry.
In the late 18th century, an anti-slavery movement began to gain momentum in British society, organised at first by a group of Quakers, supported largely by Baptists and Methodists and eventually spearheaded by the MP William Wilberforce.
The Abolition of the Slave Trade Act threatened fines of £100 for every slave found aboard a British ship - a penalty which would have been financially disastrous for the ship owners.
Though Britain abolished slavery in 1807, it did not emancipate slaves in its overseas territories until 1834.
From the abolition of slavery until the early years of the 20th Century, the Royal Navy's West Africa Squadron sailed up and down the African coast, intercepting foreign ships carrying slaves.