Metropolitan Police officer Yvonne Fletcher was shot and killed while on duty during a protest outside the Libyan embassy in London, resulting in an 11-day police siege of the building and a breakdown of Libya–United Kingdom relations.

The Metropolitan Police Service (MPS), commonly known as the Metropolitan Police, and simply known as the Met Police or the Met, is the territorial police force responsible for law enforcement and crime prevention within Greater London. In addition, it is responsible for specialised tasks throughout the United Kingdom, such as dealing with counter-terrorism throughout the UK, and the protection of certain individuals, including the monarch, royal family, governmental officials, and other designated figures. It is also referred to as an eponym as Scotland Yard or the Yard, after the location of its original headquarters in Great Scotland Yard, Whitehall, in the 19th century. The Met is presently headquartered at New Scotland Yard, on the Victoria Embankment.

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.

Relations between Libya and the United Kingdom were initially close and positive after the British Armed Forces helped rebel forces to topple Muammar Gaddafi's regime in the 2011 Libyan Civil War. British officials have visited Libya several times since then, including two visits by Prime Minister David Cameron when large crowds turned out to welcome him. The British Armed Forces are also helping to train Libya's National Army as part of wider cooperation on security matters. Security conditions have deteriorated since 2014, when the United Kingdom suspended operations from their embassy in Tripoli, into a second civil war. In June 2022, the United Kingdom re-opened its embassy in Tripoli.