Lloyds of London archives show how important the City was to transatlantic slavery

The Slave Ship, by William Turner (1840): slavers throw overboard the dead and dying as a typhoon approaches. Wikimedia

In 1783, the City of London was gripped by a court case which symbolised the brutal economics of slavery. Two years previously, the Liverpool slave ship Zong had set out from Accra, in present-day Ghana, with 442 men, women and children crammed in its hold.

By November 29 1781, according to the crew, navigational errors sent the ship off course. Fearing low water supplies, captain Luke Collingwood made a cold calculation. Over the course of a few days, he threw 132 enslaved people overboard.