In 1783 the gallows at Tyburn were moved to Newgate – the prison which had loomed over London for six centuries. Over a thousand executions took place both inside and outside its walls until it closed in 1902.
Following Newgate’s closure some newspapers reported arrangements being made at Brixton to accommodate London’s executions. The newly-founded Tatler magazine published a picture of this ‘execution shed’ being built.
I can find no evidence of an execution ever having taken place at Brixton, which in 1902 had begun a new role as London’s remand prison. Stories of the time report people being transported from the prison to Wandsworth to be hanged.
A former officer has suggested the building was used to store execution equipment, and that there was a pit which could have been used for a hanging. It’s now used as a gym for the prisoners, and there’s no sign of a pit – or come to that a gallows.