Dublin and Monaghan bombings

On the evening of 17 May 1974, the loyalist Ulster Volunteer Force (UVF) detonated four car bombs without warning in Dublin and Monaghan, Ireland, killing 33 civilians and injuring almost 300. It was the deadliest attack of the conflict known as the Troubles and the deadliest attack in the history of the Republic of Ireland. Most of the dead were young women; victims' ages ranged from four and a half months to 80 years. The bombings occurred during the Ulster Workers' Council strike, a general strike called by loyalists and unionists opposed to the Sunningdale Agreement's plan for a role for the Republic of Ireland in governing Northern Ireland and for power-sharing with Irish nationalists.

Three of the bombs exploded within about four minutes of one another during Friday evening rush hour: on Parnell Street at roughly 17:28, on Talbot Street at roughly 17:30, and at the junction of Nassau Street and South Leinster Street at roughly 17:32. Twenty-three people were killed in the Dublin blasts and three more died later of their injuries, including an entire family of four on Parnell Street. Almost ninety minutes later, at roughly 18:58, a fourth car bomb exploded outside a pub in Monaghan, killing five people outright and two more in the following weeks. Among the named dead were Antonio Magliocco and Simone Chetrit, both foreign nationals; Colette Doherty, who was nine months pregnant; Edward O'Neill, killed on Parnell Street; and Thomas Campbell, killed in Monaghan.

No one has ever been charged in connection with the bombings. The UVF, a loyalist paramilitary group that had carried out attacks in the Republic since 1969, publicly claimed responsibility in July 1993, a week after the broadcast of a Yorkshire Television documentary, Hidden Hand: The Forgotten Massacre, which named the UVF as responsible and alleged that elements of the British security forces had assisted. In its statement, issued 15 July 1993, the UVF denied any state involvement and said the operation had been planned and carried out solely by its own members.

Following a campaign by bereaved families, the Irish government appointed Mr Justice Henry Barron to investigate. His report, published on 10 December 2003, concluded it was likely that British military personnel had helped the UVF carry out the attacks, including members of a group known as the Glenanne gang, though it found insufficient evidence that senior security force figures had been involved. The report also criticised the Garda Síochána's investigation, finding that the specially appointed Garda team had been disbanded roughly two months after the bombings and had stopped its work prematurely, and it criticised the Fine Gael/Labour government of the time for showing little interest in the bombings. Ireland's parliamentary Joint Committee on Justice later described the attacks as an act of international terrorism involving British state forces.

The inquiry said its work was hindered throughout by the British government's refusal to release relevant intelligence documents, a refusal that has persisted despite parliamentary motions calling for their release and a threatened Irish case before the European Court of Justice. In May 2024, Iain Livingstone, the head of a separate British review of Troubles-era killings called Operation Denton, said there was no doubt that the Glenanne gang had colluded with British authorities in carrying out the bombings. Victims' families, organised as the group Justice for the Forgotten, continue to campaign for the release of the withheld documents.