The murder of Yvonne Fletcher, a Metropolitan Police officer, occurred on 17 April 1984, when she was fatally wounded by a shot fired from the Libyan embassy on St James's Square, London, by an unknown gunman. Fletcher had been deployed to monitor a demonstration against the Libyan leader Muammar Gaddafi, and died shortly afterwards. Her death resulted in an eleven-day siege of the embassy, at the end of which those inside were expelled from the country and the United Kingdom severed diplomatic relations with Libya.

St James's Square is the only square in the St James's district of the City of Westminster and is a garden square. It has predominantly Georgian and Neo-Georgian architecture. For its first two hundred or so years it was one of the three or four most fashionable residential streets in London. It now has headquarters of a number of well-known businesses, including BP and Rio Tinto Group; four private members' clubs, the East India Club, the Naval and Military Club, the Canning Club, and the Army and Navy Club; the High Commission of Cyprus; the London Library; and global think tank and peace-promoter Chatham House.