When Granville Sharp found escaped slave Jonathan Strong outside his brother's surgery for the poor in London's Cheapside in 1765, it was the spark that started the campaign to end the slave trade. Strong's face had been beaten to a pulp by a pistol-whipping from his owner. Over the next two years, Sharp and his brothers restored Strong to full health. But then his owner demanded him back.
For Sharp, described by TV historian Simon Schama as the patriarch of the movement to abolish the slave trade, his experience with Strong began a lifelong mission. He taught himself the law so he could assert the rights of Strong and other slaves who had escaped to London and were being pursued and often kidnapped back by their owners.
My own interest in Sharp is personal and began at an early age: he was my great-great-great-great-great uncle, and I grew up with a portrait of him on my bedroom wall.
In the early days of abolitionism, the legal arguments centred around the rights in Britain of slaves from the West Indies and America. If slavery were to be illegal in Britain, would a slave brought from overseas be a free man here?
Granville Sharp and his brothers were accomplished musicians and had a barge on which they conducted concerts. Sharp's brother William was surgeon to King George III, who regularly attended these concerts, along with members of the nobility. Granville Sharp used these connections to pursue the case for abolition. At one point he accosted Prime Minister Lord North with one of his pamphlets when he came to a concert on the barge.
If these activities sound familiar, that's because they are. It is hard to find a single activity used by modern campaigners that wasn't used by the anti-slavery movement. Sharp secured extensive newspaper coverage, which became a critical aid to mobilising public opinion. The abolitionists had their own version of the Make Poverty History wristband in the form of a medallion made by pottery manufacturer Josiah Wedgwood, on which was the legend "Am I not a man and a brother?" And when the vote in Parliament went against abolition in 1791, they began a campaign remarkably similar to the contemporary fair-trade movement, in which sugar produced by slaves in the West Indies was boycotted in favour of sugar produced by free men.
Thomas Clarkson, Sharp and others were inveterate pamphleteers. As a divinity student, Clarkson wrote an essay on slavery that started him on a lifetime of anti-slavery campaigning and made him one of the great moral writers of his day.
The anti-slavery movement can justly claim to be the first global campaign. When slaves in the plantations on the American eastern seaboard heard of the freedom promised to slaves who had fled to London, they began to defect and fight on the British side in the American War of Independence.
But slavery wasn't just a political issue involving America; it was intertwined with the British war with France of the late 18th and early 19th centuries. The 1791 vote was lost partly because the anti-abolitionists feared that France would simply take over the trade to its economic advantage. It was only when Britain's naval and economic power had increased by the early 1800s that the vote was finally won in 1807.
Anybody involved in today's global campaigns on climate change, debt relief and world trade will recognise the supreme importance of geopolitics and economic interests, as well as the cultivation of public opinion and the winning of legal arguments. The movement to abolish the slave trade was arguably the most successful campaign of all time. It was the first recognisable human rights campaign and was driven not by government and politicians, but by concerned citizens.
Apart from anything else, it shows the importance of teamwork and coalitions to winning campaigns: Granville Sharp, with his meticulous legal zeal and interest in wider political freedoms; Thomas Clarkson, with his skill in writing and systematic research; and William Wilberforce, with his parliamentary skills and political connections.
As someone who started campaigning and fundraising at the age of 14, I think there is much we can still learn from the numerous individuals whose efforts abolished the slave trade and slavery. It can take years or decades to achieve change. Real-life human stories matter as much as legal arguments. Campaigns cost money. Lasting change requires legal and policy change. But the most important lesson of all is that individuals can make a difference to the world in which they live.
For a few, such as Sharp, Clarkson and Wilberforce, or Gandhi and Baden-Powell, the impact of their work will be global and will endure for hundreds of years. For most of us, our impact as campaigners will be much more local - on our communities or on the causes we care about. But nobody should ever doubt that individuals can make a difference and that history is on our side.- Joe Saxton is founder of think tank nfpSynergy, chair of student environment and development campaign group People & Planet and chair of the Institute of Fundraising.