The Warrenpoint ambush, also known as the Narrow Water ambush, the Warrenpoint massacre or the Narrow Water massacre, was a guerrilla attack by the Provisional Irish Republican Army (IRA) on 27 August 1979. The IRA's South Armagh Brigade ambushed a British Army convoy with two large roadside bombs at Narrow Water Castle outside Warrenpoint, Northern Ireland. The first bomb was aimed at the convoy itself, and the second targeted the incoming reinforcements and the incident command point (ICP) set up to deal with the incident. IRA volunteers hidden in nearby woodland also allegedly fired on the troops, who returned fire. The castle is on the banks of the Newry River, which marks the border between Northern Ireland and the Republic of Ireland. Eighteen British soldiers were killed and over twenty were seriously injured, making it the deadliest attack on the British Army during the Troubles. An English civilian was also killed and an Irish civilian wounded, both by British soldiers firing across the border after the first blast. The attack happened on the same day that the IRA assassinated Lord Louis Mountbatten, a close relative of the British royal family. Ambush The ambush took place on the A2 road at Narrow Water Castle, just outside Warrenpoint, in the south of County Down in Northern Ireland. The road and castle are on the northern bank of the Newry River (also known as the Clanrye River), which marks the border between Northern Ireland and the Republic of Ireland. The Republic's side of the river, the Cooley Peninsula in County Louth, was an ideal spot from which to launch an ambush: it was thickly wooded, which gave cover to the ambushers, and the river border prevented British forces giving chase. First explosion On the afternoon of 27 August, a British Army convoy of one Land Rover and two four-ton lorries—carrying soldiers of the 2nd Battalion, Parachute Regiment—was driving from Ballykinler Barracks to Newry. The British Army were aware of the dangers of using the stretch of road along the Newry River and often declared it out of bounds. However, they would sometimes use it to avoid setting a pattern. At 16:40, as the convoy was driving past Narrow Water Castle, an fertiliser bomb, hidden among strawbales on a parked flatbed trailer, was detonated by remote control by IRA members watching from across the border in County Louth. The explosion caught the last lorry