Historians and anti-racism campaigners are to urge the countries that oversaw and profited from the Atlantic slave trade to recognise it as a crime against humanity, opening the way for reparations.

Next week, activists are to send a letter to the leaders of Britain, Denmark, the Netherlands, Portugal and Spain asking them to recognise the trade as an historic injustice a century and a half after it ended.

They have already convinced France to do so.