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.
The Royal Irish Regiment is an infantry regiment of the British Army. The regiment was founded in 1992 through the amalgamation of the Royal Irish Rangers and the Ulster Defence Regiment. Their oldest predecessor, the 27th Regiment of Foot, was first raised in June 1689 to fight in the Williamite War in Ireland. Other notable regiments in their lineage include the Royal Inniskilling Fusiliers, Royal Irish Rifles and the Royal Irish Fusiliers.
HQ Northern Ireland was the formation responsible for the British Army in and around Northern Ireland. It was established in 1922 and disbanded, replaced by a brigade-level Army Reserve formation, 38 (Irish) Brigade, in 2009.
The Glenanne barracks bombing was a large truck bomb attack carried out by the Provisional IRA against a British Army base at Glenanne, near Mountnorris, County Armagh. The driverless lorry was rolled down a hill at the rear of the barracks and crashed through the perimeter fence. The bombing took place on 31 May 1991 and left three soldiers killed and 14 people wounded, four of them civilians.
1st Battalion, Ulster Defence Regiment was formed in 1970 as part of the 7 original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was amalgamated with the 9th Battalion, Ulster Defence Regiment in 1984 to form the 1st/9th Battalion, Ulster Defence Regiment.
2nd Battalion, Ulster Defence Regiment was formed in 1970 as part of the seven original battalions specified in the Ulster Defence Regiment Act 1969, which received royal assent on 18 December 1969 and was brought into force on 1 January 1970. It was, along with the rest of the regiment, amalgamated with the Royal Irish Rangers in 1992 to form the Royal Irish Regiment. It had previously been amalgamated in 1991 with the 11th Battalion Ulster Defence Regiment to form the 2nd/11th Battalion Ulster Defence Regiment.
The 11th (Craigavon) Battalion, Ulster Defence Regiment was formed from companies of the 2nd Battalion Ulster Defence Regiment and the 3rd Battalion Ulster Defence Regiment in 1972. In 1991 under the reductions planned in Options for Change by the British Army, it again amalgamated with 2 UDR to form the 2nd/11th Battalion Ulster Defence Regiment.
3rd Battalion, Ulster Defence Regiment was formed in 1970 as part of the seven original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was, along with the rest of the regiment, amalgamated with the Royal Irish Rangers in 1992 to form the Royal Irish Regiment.
4th Battalion, Ulster Defence Regiment was formed in 1970 as part of the seven original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was amalgamated with the 6th Battalion, Ulster Defence Regiment in 1992 to form the 4th/6th Battalion, Ulster Defence Regiment.
5th Battalion, Ulster Defence Regiment was formed in 1970 as part of the seven original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was, along with the rest of the regiment, amalgamated with the Royal Irish Rangers in 1992 to form the Royal Irish Regiment.
The 6th Battalion, Ulster Defence Regiment was formed in 1970 as part of the seven original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was, along with the rest of the regiment, amalgamated with the Royal Irish Rangers in 1992 to form the Royal Irish Regiment.
7th Battalion, Ulster Defence Regiment was formed in 1970 as part of the 7 original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was amalgamated with the 10th Battalion, Ulster Defence Regiment in 1984 to form the 7th/10th Battalion, Ulster Defence Regiment.
The 7th/10th Battalion, Ulster Defence Regiment was formed in 1984 as a result of an amalgamation between the 7th Battalion Ulster Defence Regiment and the 10th Battalion Ulster Defence Regiment. The resultant 7/10 UDR was subsumed into the Royal Irish Rangers in 1992 as part of the amalgamation which formed the Royal Irish Regiment.
The 8th Battalion, Ulster Defence Regiment was formed on 1 December 1971 using companies, based in the east of the county, of the 6th Battalion Ulster Defence Regiment. It was, along with the rest of the regiment, subsumed into the Royal Irish Rangers in 1992 to form the Royal Irish Regiment.
The 10th Battalion, Ulster Defence Regiment was formed in 1972 from elements of the 7th Battalion, Ulster Defence Regiment creating a second battalion in Belfast. It was again amalgamated with 7 UDR in 1984 to form the 7th/10th Battalion, Ulster Defence Regiment.
The 1st/9th Battalion, Ulster Defence Regiment was formed in 1984 as a result of an amalgamation between the 1st Battalion Ulster Defence Regiment and the 9th Battalion Ulster Defence Regiment.
Brigadier Henry Joseph Patrick Baxter was an Irish born fourth generation soldier who overcame the handicap of being blind in one eye to join the army and rose to command one of the largest and most controversial regiments in the British Army.
On 2 May 1974 the Provisional Irish Republican Army (IRA) attacked a British Army base manned by the Ulster Defence Regiment (UDR) near the Northern Ireland–Republic of Ireland border at Clogher, County Tyrone. The IRA unit engaged the small base with automatic weapons, rockets and improvised mortars. Ferret armoured cars were deployed to the scene and a fierce firefight erupted. The IRA withdrew behind the border with the Republic. The assault on the outpost killed greenfinch Eva Martin and wounded another UDR soldier.
United Kingdom 
British Army 
