Became a wealthy merchant and banker in London, influential in the Society of Friends, the Quakers. One of six Quakers who set up the first association in England to work against the slave trade in 1783. In 1787 this group joined with Thomas Clarkson and others to form the London Abolition Committee, the main organisation that worked with William Wilberforce to abolish the trade. That year, Harrison was one of eight members on the sub-group that created the seal used as the template for Josiah Wedgwood’s famous medallion, featuring a kneeling African in chains holding up his hands in supplication with the words ‘Am I Not a Man and A Brother?’