7 February 1991 - the Provisional Irish Republican Army (IRA) launched three homemade mortar shells at the HQ of the Government of the United Kingdom. It was an assassination attempt on Prime Minister John Major and his Cabinet. Fortunately, the assassination attempt failed and nobody was killed.
John Major was shaken but unhurt when a mortar exploded in the enclosed garden outside where he was holding a cabinet meeting. The only causalities were a civil servant and three police officers who suffered only minor injuries.
Two of the three mortars landed on the Foreign Office green and failed to detonate. A statement from Scotland Yard said; "The third shell shook the historic residence breaking windows but did relatively little damage". The IRA claimed responsibility for the attack.
This was not the first assassination attempt on a sitting Prime Minister. The IRA bomb planted at the Grand Hotel in Brighton during the Conservative Party conference in 1984. It was a long-delay time bomb and the target was prime minister Margaret Thatcher. Thatcher escaped shaken with cuts and bruises but the blast killed five people including MP, Sir Anthony Berry (Deputy Chief Whip), Lady Shattock wife of Sir Gordon Shattock and MP Eric Taylor in addition to wounding 30 others.
Here is a newsreel of the day starting with the bombing of the Grand Hotel in Brighton.