On a plantation just outside the Jamaican capital, Kingston, we watched workers with long machetes slice down towering stalks of sugar cane with industrial precision. Sugar is still harvested by hand, when it is too wet for machines The crop is only harvested by hand on modern plantations when it rains and today there is a steady drizzle. Usually machines do the graft. But for more than 300 years until the early 19th century the machines were African slaves. Men, women and children were overworked and brutalised. Cruelty and torture meant as many as a third of all slaves...