Downing Street Mortar Attack
The Downing Street mortar attack was carried out by the Provisional Irish Republican Army (IRA) on 7 February 1991. The IRA launched three homemade mortar shells at 10 Downing Street, London, the headquarters of the British government, in an attempt to assassinate Prime Minister John Major and his war cabinet, who were meeting to discuss the Gulf War.
One of the 140 pound (64 kg) mortar shells exploded in the back garden of Number 10, a few yards from the Cabinet Office. Due to bomb-resistant windows, none of the cabinet were hurt, though four other people received minor injuries, including two Metropolitan Police officers. The other two shells overshot Downing Street and landed on a green nearby.
Additional Reading:
The PIRA and the Development of Mortars
Tactical Innovation and the Provisional Irish Republican Army