The Infantry of the British Army comprises 49 infantry battalions, from 19 regiments. Of these, 33 battalions are part of the Regular army and the remaining 16 a part of the Army Reserve. The British Army's Infantry takes on a variety of roles, including armoured, mechanised, air assault and light.
Options for Change was a restructuring of the British Armed Forces in summer 1990 after the end of the Cold War.
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.
The Queen's Regiment (QUEENS) was an infantry regiment of the British Army formed in 1966 through the amalgamation of the four regiments of the Home Counties Brigade. Then, until 1971 the regiment remained one of the largest regiments in the army, with 10 battalions, however these were reduced to just six, and later five battalions. Following the dissolution of the Soviet Union, the Options for Change reform was published and the regiment amalgamated with the Royal Hampshire Regiment to form the Princess of Wales's Royal Regiment.
The Royal Irish Rangers was a regular infantry regiment of the British Army with a relatively short existence, formed in 1968 and later merged with the Ulster Defence Regiment in 1992 to form the Royal Irish Regiment.
The Royal Irish Rifles was an infantry rifle regiment of the British Army, first created in 1881 by the amalgamation of the 83rd Regiment of Foot and the 86th Regiment of Foot. The regiment saw service in the Second Boer War, the First World War, the Second World War, and the Korean War.
The Royal Inniskilling Fusiliers was an Irish line infantry regiment of the British Army in existence from 1881 until 1968. The regiment was formed in 1881 by the amalgamation of the 27th (Inniskilling) Regiment of Foot and the 108th Regiment of Foot.
The Prince of Wales's Division was a British Army command, training and administrative apparatus designated for all land force units in the West of England and Wales. It merged with the Scottish Division, to form the Scottish, Welsh and Irish Division; at the same time the Mercian Regiment joined with the King's Division.
A large regiment is a multi-battalion infantry formation of the British Army. First formed in the 1960s, large regiments are the result of the amalgamation of a number of existing single-battalion regiments, and perpetuate the traditions of each of the predecessor units.
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.
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.
The 9th Battalion, Ulster Defence Regiment was formed in 1972 from two companies of the 1st Battalion Ulster Defence Regiment creating a second battalion in County Antrim. It was amalgamated with 1 UDR in 1984 to form 1/9 UDR.
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.
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.
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 2nd//11th Battalion, Ulster Defence Regiment was formed in 1991 as a result of an amalgamation between the 2nd Battalion Ulster Defence Regiment and the 11th Battalion Ulster Defence Regiment. The resultant 2/11 UDR was subsumed into the Royal Irish Rangers in 1992 as part of the Options for Change amalgamations and was renamed the 6th Battalion Royal Irish 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.
United Kingdom 
British Army 