Which British prime minister was assassinated?

Spencer Percival was the ony British prime minister to be assassinated on May eleventh 1812 in the lobby of the house of commons by John Bellingham.
The Rt Hon Spencer Perceval is the only British Prime Minister to have been assassinated. John Bellingham shot him through the heart with a pistol in the lobby of the House of Commons at 5:15pm on 11 May 1812.