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 mortar shells exploded in the back garden of Number 10, yards from the Cabinet Office. Due to the 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. Background During the Troubles, as part of its armed campaign against British rule in Northern Ireland, the Provisional Irish Republican Army (IRA) repeatedly used homemade mortars against targets in Northern Ireland. The most notable occasion was the 1985 Newry mortar attack which killed nine members of the Royal Ulster Constabulary (RUC). The IRA carried out many attacks in England, but none involved mortars. In December 1988, items used in mortar construction and technical details regarding the weapon's trajectory were found during a raid in Battersea, South London, by members of the Metropolitan Police Anti-Terrorist Branch. In the late 1980s, Prime Minister Margaret Thatcher was top of the IRA's list for assassination, following the failed attempt on her life in the Brighton hotel bombing. Security around Downing Street had been stepped up at a cost of £800,000 following increased IRA activity in England in 1988, including the addition of a police guard post and security gates at the end of the street. Plans to leave a car bomb on a street near Downing Street and detonate it by remote control as Thatcher's official car was driving by had been ruled out by the IRA's Army Council owing to the likelihood of civilian casualties, which some Army Council members argued would have been politically counter-productive. Preparation The Army Council instead sanctioned a mortar attack on Downing Street and, in mid-1990, two IRA members travelled to London to plan the attack. One of the IRA members was knowledgeable about the trajectory of mortars and the other, from the IRA's Belfast Brigade, was familiar with their manufacture. An active service unit bought a Ford Transit van and rented a garage. An IRA co-ordinator procured the explosives and materials needed to make the