Terrorist organization fighting for a unified republican Ireland. A development from the Irish Republican Brotherhood and the Fenian Brotherhood, it was organized by Sinn Fein in 1919 as a nationalist armed force. Its first commander in Ireland was Michael Collins. From 1919 to 1921 it fought an effective guerrilla campaign against British forces in Ireland. Following the establishment of the Irish Free State a minority of the IRA continued to fight for a united sovereign Ireland. These forces were defeated by the Free State army in 1922–23 and the organization went underground. Bomb explosions for which the IRA was held responsible occurred in England in 1939 and hundreds of its members were imprisoned in Britain and Ireland during World War II. In 1956 violence erupted in Northern Ireland and the IRA performed a series of border raids. Following the outbreak of the current ‘Troubles’ in Northern Ireland, the IRA split into Provisional and Official wings (1969). The Officials subsequently abandoned violence but the Provisionals and another group, the Irish National Liberation Army (INLA), staged assassinations and bombings in both Northern Ireland and Britain. These include the murder of Lord Mountbatten and the British MP Airey Neave in 1979, a bomb attack on the entire British cabinet in Brighton in 1984, a bombing in Enniskillen on Remembrance Day 1987, attacks on British military bases in England and Germany in 1989, the murder of Ian Gow MP in 1990, mortar attacks on Downing Street (1991) and on Heathrow Airport (1994), a bomb in the City of London (1992), and another in Warrington in 1993. In August 1994 the IRA announced a complete cessation of its military operations, following peace initiatives by the British and Irish governments and by Northern Ireland politicians. However, the issue of decommissioning IRA weapons became a stumbling block in the progress towards all-party talks on a lasting peace settlement. The ceasefire broke down in 1995, with the resumption of IRA bombing campaigns in mainland Britain, notably in London Docklands and Manchester. After a further ceasefire, Sinn Fein was admitted to peace talks in 1997. In 1998 the Good Friday agreement was signed but the issue of decommissioning continued to hinder the peace process. The IRA finally began the process of placing its weapons ‘beyond use’ in 2001 and announced the completion of this process and the end of its armed campaign in 2005.