Operation Banner was the operational name for the British Armed Forces' operation in Northern Ireland from 1969 to 2007, as part of the Troubles. It was the longest continuous deployment in British military history. The British Army was initially deployed, at the request of the unionist government of Northern Ireland, in response to the August 1969 riots. Its role was to support the Royal Ulster Constabulary (RUC) and to assert the authority of the British government in Northern Ireland. This involved counter-insurgency and supporting the police in carrying out internal security duties such as guarding key points, mounting checkpoints and patrols, carrying out raids and searches, riot control and bomb disposal. More than 300,000 soldiers served in Operation Banner. At the peak of the operation in the 1970s, about 21,000 British troops were deployed, most of them from Great Britain. As part of the operation, a new locally-recruited regiment was also formed: the Ulster Defence Regiment (UDR).

Operation Demetrius was a British Army operation in Northern Ireland on 9–10 August 1971, during the Troubles. It involved the mass arrest and internment of people suspected of being involved with the Irish Republican Army (IRA), which was waging an armed campaign for a united Ireland against the British state. It was proposed by the Unionist government of Northern Ireland and approved by the British Government. Armed soldiers launched dawn raids throughout Northern Ireland and arrested 342 in the initial sweep, sparking four days of violence in which 20 civilians, two IRA members and two British soldiers were killed. All of those arrested were Irish republicans and nationalists, the vast majority of them Catholics. Due to faulty and out-of-date intelligence, many were no longer involved in republican militancy or never had links with the IRA. Ulster loyalist paramilitaries were also carrying out acts of violence, which were mainly directed against Catholics and Irish nationalists, but no loyalists were included in the sweep.