John Bellingham fired a single shot from a pistol, fatally wounding prime minister Spencer Perceval in the chest. Perceval collapsed immediately, and despite efforts to save him, he died shortly afterward.

Walpole was appointed First Lord of the Treasury, Chancellor of the Exchequer and Leader of the House of Commons. This made him the de facto Prime Minister and, while the title was not officially recognized at the time, Walpole wielded considerable power and influence.