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.

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.

Between 1980 and 1984 Gaddafi had ordered the deaths of several exiled opponents of his regime; bombings and shootings, targeted at Libyan dissidents, occurred in Manchester and London.

The inquest into Fletcher's death reached the verdict that she was "killed by a bullet coming from one of two windows on the west side of the front on the first floor of the Libyan People's Bureau".

Two years after Fletcher's murder, the event became a factor in the decision by the British prime minister, Margaret Thatcher, to allow the US bombing of Libya from bases in the UK.

In 1999, a warming of diplomatic relations between Britain and Libya led to a statement from the Libyan government admitting culpability in Fletcher's shooting, and the payment of compensation.

[19] During the night of 16–17 April a delegation from the People's Bureau attended a meeting at the Foreign and Commonwealth Office to complain about the forthcoming demonstration, and ask that it be stopped.

[19] The British political scientist Richard J. Aldrich writes that these messages were intercepted and decrypted by the Government Communications Headquarters (GCHQ), but not in time to avoid the shooting.

[21] The authorised history of MI5, while not specifying from where the organisation received the information, says that "it was not until after the demonstration on the 17th that the Service learned" of the three options proposed by the People's Bureau to Tripoli.

[19][b] On the morning of 17 April, police workmen placed crowd control barriers in St James's Square in preparation for the demonstration.

[30] While the demonstrators were moved into Charles II Street, Fletcher was aided by her colleagues; as she lay in the road outside the People's Bureau, she advised them to "keep calm".

The garage entrance at the rear of the People's Bureau was not sealed off until at least ten minutes after the shooting, and in that time some of those inside departed the premises through that exit.

[35] Events spread to Libya soon after the shooting, as around 60 members of the Revolutionary Guard Corps surrounded the British embassy in Tripoli, and put the premises under siege, trapping the staff of 25—including Oliver Miles, the ambassador.

[38]From the angle of the entry wound, and Fletcher's position in the street—captured on news cameras seconds before she was shot—West established that the shot had come from the first floor of the embassy.

[37][40] The following day Gaddafi appeared on Libyan television and blamed the British police and security forces for the attack; he said that "we are surprised how a responsible state like England carry on [sic] committing this crime".

The government also put the Special Air Service on standby; they flew from Stirling Lines, their base in Credenhill, Herefordshire, to London in preparation.

Each person was frisked, photographed and questioned, but when attempts were made to fingerprint the men, they objected and the neutral intermediaries advised the police that this was not allowed.

The police search of the bureau found 4,367 rounds of ammunition, three semi-automatic pistols, four .38 revolvers and magazines for Sterling submachine guns.

[57] The jury concluded that Fletcher "was killed by a bullet coming from one of two windows on the west side of the front on the first floor of the Libyan People's Bureau".

[64] In 1986 Thatcher agreed to the use of Royal Air Force bases by American aircraft involved in the bombing of Libya; she said in the House of Commons that the murder of Fletcher weighed in her decision.

[64] Abdul Fatah Younis, Libya's Minister for Public Security, met Christopher Long, Britain's ambassador to Egypt in 1992.

[71][72] In a statement to the House of Commons, the Foreign Secretary, Robin Cook announced: Libya accepts general responsibility for the actions of those in the Libyan People's Bureau at the time of the shooting.

[73]On 24 February 2004 the Today programme on BBC Radio 4 reported that Shukri Ghanem, the Libyan prime minister, had claimed his country was not responsible for Fletcher's murder or for the Lockerbie bombing.

He advised that Abdulmagid Salah Ameri, a junior diplomat in the People's Bureau at the time of the shooting, had been identified by witnesses who had observed him firing a weapon from the embassy window.

[81] The same year it was established that during trade negotiations between Britain and Libya in 2006, an agreement was reached that Fletcher's killer would not be extradited for trial in the UK.

[84] The following month The Sunday Telegraph named Salah Eddin Khalifa, a high-level member of the former regime, as the pro-Gaddafi student who shot Fletcher.

[90] In April 1984 the film director Michael Winner wrote to The Times to suggest that a memorial be placed in St James's Square "to commemorate not only the horrific death of this brave young girl, but also be a constant reminder to her killers of the feelings of the British people".

On 1 February 1985 her memorial was unveiled in St James's Square by Thatcher, in a ceremony attended by the leaders of the main British political parties.

[94]The granite and Portland stone commemorative pillar lies in the north-east corner of St James's Square, facing the former Libyan embassy.

Westminster City Council altered part of the pavement with a rounded extension into the roadway to create an area for people to stand in front of it.