An IRA bombing in County Down, Northern Ireland, kills three members of the UDR.

The Irish Republican Army (IRA) is a name used by various resistance organizations in Ireland throughout the 20th and 21st centuries. Organisations by this name have been dominantly Catholic and dedicated to anti-imperialism through Irish republicanism, the belief that all of Ireland should be an independent republic free from British colonial rule.

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).

On 9 April 1990, the South Down Brigade of the Provisional Irish Republican Army (IRA) detonated a massive improvised land mine under a British Army convoy outside Downpatrick, County Down, Northern Ireland. Four soldiers of the Ulster Defence Regiment (UDR) were killed, the regiment's greatest loss of life since 1983.

The Ulster Defence Regiment (UDR) was an infantry regiment of the British Army established in 1970, with a comparatively short existence ending in 1992. Raised through public appeal, newspaper and television advertisements, their official role was the "defence of life or property in Northern Ireland against armed attack or sabotage" but unlike troops from Great Britain they were never used for "crowd control or riot duties in cities". At the time the UDR was the largest infantry regiment in the British Army, formed with seven battalions plus another four added within two years.