For two hundred years, the abolition of slavery in Britain has been a cause for self-congratulation - but no longer. In 1807, Parliament outlawed the slave trade in the British Empire, but for the next quarter of a century, despite heroic and bloody rebellions, more than 700,000 people in the British colonies remained enslaved. And when a renewed abolitionist campaign was mounted, making slave ownership the defining political and moral issue of the day, emancipation was fiercely resisted by the powerful 'West India Interest'.