On Monday, 11 May 1812, John Bellingham made his way to the Palace of Westminster. In the lobby leading to the House of Commons, he took out a concealed pistol and shot the Prime Minister, Spencer Perceval. There was no mystery about the killer's identity, but why did he do it? "The Assassination of the Prime Minister" has all the ingredients of a non-fiction thriller: suspense, revenge, personal tragedy and murder. At the heart is the extraordinary story of how an honest businessman ended up imprisoned in a rat-infested Russian gaol for six years, refused all help by his own government.Unable to obtain the justice he thought was his due, he did the only thing he felt he could to express his outrage and get for himself a kind of natural justice. He shot the British Prime Minister. David Hanrahan's lively and colourful narrative does full justice to this extraordinary tale of neglect and obsession. He paints a convincing and moving picture of Bellingham's desperation and explores the reasons for the ambassador's failure to take any action to help him and the indifference shown by government to his petitions once he had managed to get back home.