Book excerpt: When Thomas Harding discovered that his family had profited from slavery, he set out to interrogate the choices of his ancestors and Britain's role in this terrible history. His investigation took him to Demerara (now Guyana), the site of an uprising by enslaved people in 1823, the largest in the British Empire and a key trigger in the abolition of slavery. Charting the dramatic build-up to this landmark event through the eyes of four people - an enslaved man, a missionary, a colonist, and a slaveholder - Harding lays bare the true impact of years of unimaginable cruelty and incredible courage and asks how those who benefitted from slavery can take responsibility for the White Debt.