Due to bomb-resistant windows, none of the cabinet were hurt, though four other people received minor injuries, including two Metropolitan Police officers.

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.

[3][4] 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.

They reconnoitred locations in Whitehall to find a suitable place from which the mortars could be fired at the back of 10 Downing Street, the official residence and office of the British prime minister.

[3][5] Once preparations were complete, the two IRA members returned to Ireland, as the group's leadership considered them valuable personnel and did not wish to risk them being arrested in any follow-up operation by the security services.

[3] In November 1990, Thatcher unexpectedly resigned from office, but the Army Council decided the planned attack should still go ahead, targeting her successor John Major.

As well as Major, those present included politicians Douglas Hurd, Tom King, Norman Lamont, Peter Lilley, Patrick Mayhew, David Mellor and John Wakeham; civil servants Robin Butler, Percy Cradock, Gus O'Donnell and Charles Powell; and Chief of the Defence Staff David Craig.

[5][8] As the meeting began, an IRA member was driving the van to the launch site at the junction of Horse Guards Avenue and Whitehall, about 200 yards (180 m) from Downing Street.

[2][12] No members of the cabinet were hurt, but four people received minor injuries, including two police officers injured by flying debris.

[9] The head of the Metropolitan Police Anti-Terrorist Branch, Commander George Churchill-Coleman, described the attack as "daring, well planned, but badly executed".

[12] Peter Gurney, the head of the Explosives Section of the Anti-Terrorist Branch who defused one of the unexploded shells, gave his reaction to the attack:[10] It was a remarkably good aim if you consider that the bomb was fired 250 yards [across Whitehall] with no direct line of sight.