From the website of The Abolition Project:
“Granville Sharp was a civil servant and political reformer. He was one of the 12 men who, in 1787, formed the Society for Effecting the Abolition of the Slave Trade and was the first chairman of the Society. His interest in the issue, however, went back much further.
At a time when most abolitionists argued that the Slave Trade was wrong because of the terrible conditions in which enslaved people were kept, he (along with Anthony Benezet) went further, arguing that the very nature of slavery itself was evil.
He also used his skills to fight a series of legal battles to prevent enslaved people being taken out of England by force. Many black people resisted enlavement and many escaped from their ‘owners’. However, whether they had escaped, been abandoned or had always been free, they were in constant danger of capture or recapture by ‘slave-hunters’.
In 1767, Granville Sharp and his brother William (a surgeon) helped a badly injured man, Jonathan Strong, who had been brought to London from Barbados by a plantation owner named David Lisle. Strong had been thrown onto the streets after being beaten about the head with a pistol. He was so badly injured that he was nearly blind and he could hardly walk. They took him to St. Bartholomew’s Hospital. After he regained his health, they helped him to find work as a messenger.
Quite by chance, the man that had assaulted him, saw him and, without capturing him, sold him for £30 to a Jamaican planter. Two slave hunters kidnapped and imprisoned Strong while they waited for a ship to take him to the Caribbean. Strong enlisted Granville Sharp’s help. Sharp demanded that Strong be taken before the Lord Mayor, who declared him a free man.
In 1769, Sharp published his findings in a pamphlet: ‘A representation of the injustice and dangerous tendency of tolerating slavery in England’. Sharp devoted himself to fighting the notion that an enslaved person remained, in law, the property of his master, even on English soil. He did this both by his writings and in the courts of law.
He became the leading defender of African people in London and saved many African people from being sent back to slavery in the West Indies, often at his own expense. In 1771 a slave, James Somerset, who had been brought from Jamaica to Britain, ran away. He was recaptured and put on a ship bound for Jamaica. Sharp intervened and put the case before Lord Mansfield, the Lord Chief Justice of England. Sharp hoped this case would finally settle whether it was lawful to hold people as slaves in England and Wales. After many months of legal argument, Mansfield finally decided that a master had no right to force an enslaved person to return to a foreign country. Somerset was freed.
Although this judgment did not actually state that slavery was illegal in England, it laid down the important notion that an enslaved person could not be forcibly removed from England. London’s African community celebrated this important victory; they had followed the case closely and made sure that there was always an African delegation in court.
Sharp was also involved in other legal cases, such as the slave ship Zong (see The Middle Passage). Cases such as this help to raise public awareness of the horrors of slavery and started to turn public opinion against the slave trade. In May 1787, he joined with Thomas Clarkson and nine Quakers, to form the Society for Effecting the Abolition of the Slave Trade and continued to work for abolition until the act was passed in 1807. However, Granville Sharp was not to see the final abolition of slavery in the British Colonies, as he died on 6th July, 1813.”