By Brian Wheeler
Political reporter, BBC News
If you have ever signed a petition, worn a charity wristband or taken part in a demonstration you owe something to Thomas Clarkson.
Make Poverty History was part a tradition stretching back 200 years
The preacher's son from Cambridgeshire is one of the great unsung heroes of the fight to abolish slavery and the slave trade.
But what is even less well known is the extent to which Clarkson and his fellow abolitionists set the template for all future protest movements.
Every modern campaigning technique - from celebrity endorsement to political lobbying and consumer boycotts - was pioneered by the abolitionists more than 200 years ago.
The growth of their movement went hand in hand with the birth of Parliamentary democracy and the idea that if enough people band together around a common cause they can change the law of the land.
Everything that followed - from the Suffragettes to the US civil rights movement in 1960s to Live Aid and Make Poverty History owes a debt to the abolitionists.
And there is still much that today's campaigners can learn from their techniques.
The abolitionist movement began in the Quaker meeting houses of the 1770s, with the establishment of the Committee for the Abolition of the Slave Trade.
At that time, the slave trade was seen as a legitimate, profitable and even "genteel" profession.
The pro-slavery lobby attempted to dehumanise Africans by claiming they lived like savages and were grateful for the opportunity to escape Africa. They were said to enjoy the crossing and enjoy good living conditions on the plantations.
The abolitionists, led by Clarkson, set out to provide evidence that none of these things were true.
Clarkson was adept at getting decision makers to take up the slavery issue. He worked in the same way that political lobbyists do today.
He helped to persuade MP William Wilberforce to become the parliamentary spokesperson for the campaign.
He helped organise a 300,000 strong boycott of slave-harvested sugar, in the first known example of consumer protest.
The celebrities of the day also queued up to lend their support.
Thomas Clarkson was adept at lobbying MPs
Actors, cartoonists and artists like JMW Turner and William Blake provided visual representations of slavery that reached audiences in ways the written word could not.
In 1787, Josiah Wedgwood designed a seal for the campaign, the forerunner of today's campaign logos.
The image depicts an African man kneeling in supplication, or perhaps in prayer, under the slogan 'Am I not a man and a brother?'
The image would probably alienate many potential supporters if used today.
But in the late 1700s it pushed all the right buttons, particularly among Christians who felt slavery went against God's teachings.
The abolitionists were also pioneers of investigative journalism.
The first campaign logo?
Clarkson interviewed sailors, ships' doctors and traders in London, Bristol and Liverpool to document the treatment of enslaved people.
He bought shackles, thumbscrews and a device for force-feeding slaves who went on hunger strike, to provide physical evidence of abuse and confirm the testimonies he collected.
But - in another forerunner of today's campaigning techniques - Clarkson would present the evidence in a rational, dispassionate way, free from the moral exhortations and blood-curdling rhetoric often seen on religious pamphlets of the day.
The abolitionists also knew how to appeal to the self-interest of their target audience, for example producing statistics to show that almost as many British sailors as Africans died on slave ships.
And they made the subject real to their audience by holding public meetings where freed slaves would tell harrowing stories of brutality and abuse.
The abolitionists also showed how it is possible to influence the political agenda through more subtle means.
If you can get the middle classes talking about an issue at dinner parties, it is not long before it is being discussed in Parliament.
Today's campaigns owe much to the abolitionists
"We totally copy those methods," says Sarah Green, of Amnesty International, who says the abolition movement continues to be an "inspiration".
"It shows that if you set your objectives clearly, to be clear and singular about what you want and go about it in a cunning and creative way, you can achieve what you want to achieve."
The abolitionists were the first membership organisation to campaign for political change, forming local groups and sending out newsletters to keep members updated on progress.
Perhaps the biggest difference with today's campaigns was in the speed of transmission.
Today's campaigners can spread their message around the world at the click of a mouse, but it would take Clarkson two years to complete a book tour of Britain.
About 50% of Britain's population were also illiterate in the late 18th Century, so the anti-slavery campaigners had to use visual imagery to get their message across.
One picture, showing a cross-section of the slave ship 'Brookes' packed with 482 enslaved people was reproduced on 7,000 posters around the country and remains one of the most enduring images associated with the slave trade.
Nevertheless, it only took the abolitionists 20 years to fundamentally change public opinion - and the law - on slavery.
"It was an incredible achievement. Even today it can take decades to change public attitudes," says Mike Kaye of Anti-Slavery International.
The difference is that today there are many single-issue campaigns competing for public attention.
But the size of the public response to campaigns such as Make Poverty History or the Stop the War and Countryside Alliance marches shows that there is still a huge public appetite for mass membership protests.
"I don't think there is any reason to be pessimistic or to fear that we have lost our campaigning edge," says Mr Kaye.