ABOLITION: DETESTABLE TRADE By Jonathan Schofield Manchester was the scene of the very first mass meeting opposing the slave trade. In 1787, abolitionist campaigner Thomas Clarkson found himself welcomed in Manchester after being attacked in Liverpool. His speech at the old Collegiate Church, now the Cathedral, led to a petition which was signed by a fifth of the city's population. City guide, Jonathan Schofield, tells the story of that speech. Your thoughts about this video