Operation Banner, the presence of the British Army in Northern Ireland, and the longest-running British Army operation ever, comes to an end.

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).

Northern Ireland is a part of the United Kingdom in the north-east of the island of Ireland. It has been variously described as a country, province or region. Northern Ireland shares an open border to the south and west with the Republic of Ireland. At the 2021 census, its population was 1,903,175, making up around 3% of the UK's population and 27% of the population on the island of Ireland. The Northern Ireland Assembly, established by the Northern Ireland Act 1998, holds responsibility for a range of devolved policy matters, while other areas are reserved for the UK Government. The government of Northern Ireland cooperates with the government of Ireland in several areas under the terms of the Good Friday Agreement. The Republic of Ireland also has a consultative role on non-devolved governmental matters through the British–Irish Governmental Conference (BIIG).