LONDON - SEPTEMBER 04:  Archbishop Desmond Tutu unveils a memorial to the abolition of the Transatlantic Slave Trade in Fen Court on September 4, 2008 in London.'Gilt of Cain' by artist Michael Visocchi and poet Lemn Sissay commemorates the bicentenary of the abolition of the slave trade. Getty Images logo Getty Images 14 months ago

LONDON - SEPTEMBER 04: Archbishop Desmond Tutu unveils a memorial to the abolition of the Transatlantic Slave Trade in Fen Court on September 4, 2008 in London.'Gilt of Cain' by artist Michael Visocchi and poet Lemn Sissay commemorates the bicentenary of the abolition of the slave trade.