57 Infantry brigades of the British Army in World War I

During the First World War, 259 infantry brigades were raised by the British Army, two by the Royal Navy, and one from the Royal Marines. Of these brigades, fifty-three were held in reserve or only used for training, while another nine only served in British India.

The 1st Armoured Infantry Brigade is an infantry brigade of the British Army with a long history including service during both the First and the Second World Wars. It is based at Tidworth Camp. Previously, it has been designated 1st (Guards) Brigade, 1st Infantry Brigade, 1st Mechanised Brigade, and under the initial Army 2020 reforms assumed the title of 1st Armoured Infantry Brigade.

The 1st Guards Brigade was an infantry brigade of the British Army, formed in the First World War. It was formed in August 1915 by the redesignation of the 4th (Guards) Brigade on its transfer from the 2nd Division to the Guards Division. It served with the Guards Division on the Western Front for the rest of the war.

The 1st Armoured Infantry Brigade is an infantry brigade of the British Army with a long history including service during both the First and the Second World Wars. It is based at Tidworth Camp. Previously, it has been designated 1st (Guards) Brigade, 1st Infantry Brigade, 1st Mechanised Brigade, and under the initial Army 2020 reforms assumed the title of 1st Armoured Infantry Brigade.

The 2nd Guards Brigade was an infantry brigade of the British Army, formed in the First World War. It was formed in France in August 1915 with two Guards battalions already on the Continent and another two from England. It served with the Guards Division on the Western Front for the rest of the war.

The 2nd Infantry Brigade was a regional brigade of the British Army, active since before the First World War. It was the regional formation of the Army in the South East of England–the Brigade commanded and administered soldiers throughout Kent, Surrey and Sussex–but also Brunei. In December 2014 the Brigade merged with 145 (South) Brigade to form Headquarters 11th Infantry Brigade and Headquarters South East.

The 3rd Infantry Brigade was a Regular Army infantry brigade of the British Army, part of the 1st Infantry Division. Originally formed in 1809, during the Peninsular War, the brigade had a long history, seeing action in the Second Anglo-Afghan War, and during both the First and the Second World Wars.

The 3rd Guards Brigade was an infantry brigade of the British Army in World War I. It was formed in France in August 1915 with two battalions already on the Continent and another two from England. It served with the Guards Division on the Western Front for the rest of the war.

The 223rd Brigade was a Home Defence formation of the British Army in the First and the Second World Wars. It existed under several variations of the 223 Brigade title, and was eventually converted into an airborne formation.

The 5th Infantry Brigade was a regular infantry brigade of the British Army that was in existence since before the First World War, except for a short break in the late 1970s. It was an Airborne Brigade from the early 1980s until amalgamating with 24th Airmobile Brigade, in 1999, to form 16 Air Assault Brigade.

The 6th Infantry Brigade was a regular infantry brigade of the British Army that was in existence during the Second Boer War, the First World War and the Second World War and later formed part of British Army of the Rhine.

The 7th Infantry Brigade and Headquarters East is a formation in the British Army with a direct lineage to 7th Armoured Brigade and a history that stretches back to the Napoleonic Wars. It saw active service in the Crimean War, the Second Boer War and both the First and the Second World Wars. In 2014, the 7th Armoured Brigade was re-designated as 7th Infantry Brigade, thereby ensuring that the famed "Desert Rats" continue in the British Army's Order of battle.

The 8th Infantry Brigade was an infantry brigade of the British Army that saw active service in both the First and the Second World Wars, before being disbanded and reactivated in the 1960s. The brigade was finally being disbanded in 2006. It was formed before the First World War as part of the 3rd Division. As part of that division it spent the entire war on the Western Front from 1914 to 1918 in the First World War. The brigade was also active during the Second World War.

The 11th Infantry Brigade and Headquarters South East is a regular British Army brigade formation that is part of the Army's 'Adaptable Force' meaning it has operational units under command, as well as regional responsibilities across the South East of England. The Brigade was re-established on 1 August 2014 when 145 (South) Brigade was re-designated as Headquarters 11th Infantry Brigade. In December 2014 the brigade merged with 2 Brigade to form Headquarters 11th Infantry Brigade and Headquarters South East. 11th Infantry Brigade is also regionally aligned with the southern and eastern African region as part of defence engagement. In 2021 it was announced that the brigade will be re-designated as 11 Security Forces Assistance Brigade.

The 12th Armoured Infantry Brigade, formerly the 12th Mechanized Brigade, is a regular brigade of the British Army which has been in almost continuous existence since 1899 and now forms part of 3rd Division.

The 15th Infantry Brigade, later 15 Brigade, was an infantry brigade of the British Army. It was part of the regular 5th Infantry Division during the First World War and Second World War, and was subsequently part of the 2nd Infantry Division in the north of the United Kingdom, with specific responsibility for the areas of North East England and Yorkshire and the Humber.

The 17th Infantry Brigade was an infantry brigade formation of the British Army which provided active service in the Second Boer War and both the First and Second World Wars. It was mainly composed of Regular Army battalions.

The 19th Light Brigade was a Regular Army infantry brigade of the British Army. As the 19th Infantry Brigade fought in the First and Second world wars.

The 24th Infantry Brigade was an infantry brigade of the British Army from the First World War. It was reraised during the Second World War, as the 24th Infantry Brigade (Guards). During various designations, the brigade was active throughout the Cold War and existed until 1999, when it was merged with the 5th Airborne Brigade to become the 16 Air Assault Brigade.

The 29th Infantry Brigade was an infantry brigade unit of the British Army. It was originally raised in 1914 and saw service during the First and Second World Wars and the Korean War.

The 35th Brigade was an infantry brigade formation of the British Army that saw active service in both the First and the Second World Wars.

The 37th Brigade was an infantry brigade of the British Army that served in both the First and the Second World Wars.

The 39th Infantry Brigade was a military formation of the British Army that was first established during the First World War and reformed in the 1950s.

The 42nd Infantry Brigade, also known as 42 Brigade, was a brigade of the British Army.

The 43rd Infantry Brigade was a brigade of the British Army during the First and Second World Wars, and later, as 43 (Wessex) Brigade, a regional headquarters from 1985 to 2014.

The 45th Infantry Brigade was an infantry brigade of the British Army that saw active service in both the First and the Second World Wars with 15th (Scottish) Infantry Division.

The 52nd Infantry Brigade was a formation of the British Army, which was first formed in 1914 as part of Kitchener's Army. The brigade was disbanded in 1919, but reformed in British India during the Second World War and disbanded in 1945. It was again formed in 1982, and existed until 2010.

The 53rd Brigade was an infantry brigade of the British Army that saw active service in both the First and Second World Wars. In the First World War, the brigade served with 18th (Eastern) Division and during the Second with the 18th Infantry Division.

The 56th Infantry Brigade was an infantry brigade of the British Army that saw active service in both the First and the Second World Wars.

The 71st Infantry Brigade was an infantry brigade formation of the British Army that saw active service during both the First and Second World Wars.

The 72nd Brigade was an infantry brigade formation of the British Army in the First World War and the Second World War.

The 77th Brigade is a British Army formation, created in January 2015 by renaming the Security Assistance Group which was created under the Army 2020 concept. It is based at Denison Barracks in Hermitage, Berkshire and became operational in April 2015.

The 87th Brigade was an infantry brigade formation of the British Army that saw service in World War I. It was originally formed in 1915 from four Regular Army battalions serving away from home in numerous parts of the British Empire. Its first commander was General W.R. Marshall, with C.H.T.Lucas taking command in August 1915. The brigade was assigned to the 29th Division and served in the Gallipoli Campaign from 1915 - 1916, preceding a short time in the Middle Eastern theatre, later being sent to the Western Front in time to attack at Beaumont Hamel on July 1st 1916, and remaining on that front for the rest of the war.

The 88th Brigade was an infantry brigade formation of the British Army, raised for service in the First World War. It was originally formed from regular army battalions serving away from home in the British Empire. The brigade was assigned to the 29th Division and served on the Western Front and the Gallipoli Campaign and in the Middle East.

98th Brigade was an infantry formation of the British Army created to command 'Kitchener's Army' units during World War I. It served on the Western Front from 1916, seeing action on the Somme, at Arras and Ypres, during the German spring offensive and the final Allied Hundred Days Offensive.

The Tyneside Irish Brigade was a British First World War infantry brigade of Kitchener's Army, raised in 1914. Officially numbered the 103rd Brigade, it contained four Pals battalions from Newcastle upon Tyne, largely made up of men of Irish extraction..

The 125th Brigade was an infantry brigade formation of the British Army that saw active service during both the First and Second World Wars. It was assigned to the 42nd Division and served in the Middle East and later in the trenches of the Western Front in the First World War. In the Second World War the brigade, now redesignated 125th Infantry Brigade, fought in Belgium and France before being evacuated at Dunkirk and was then converted into 10th Armoured Brigade.

The 126th Brigade was an infantry brigade of the British Army during the First World War and the Second World War. It was assigned to the 42nd Division and served in the Middle East and on the Western Front in the Great War. In the Second World War, now as the 126th Infantry Brigade, it served again with the 42nd Division in France and was evacuated at Dunkirk and then later converted into 11th Armoured Brigade.

The 127th (Manchester) Brigade was an infantry brigade of the British Army that saw active service during both the First and Second World Wars. It was assigned to the 42nd Division and served in the Middle East and on the Western Front in the First World War.

The 132nd Infantry Brigade was an infantry brigade of the British Army that remained in British India during the First World War. During the Second World War, it served with the 44th Infantry Division in Belgium and France, later being evacuated at Dunkirk and seeing service again in North Africa at El Alamein before being disbanded in January 1943.

The 140th Brigade was an infantry brigade formation of the British Army's Territorial Army (TA) that had its origins in a South London Brigade of the former Volunteer Force. It served on the Western Front in the First World War and was recreated during the Second World War where it served only in the United Kingdom as a training formation.

The 141st Brigade was an infantry brigade of the Territorial Army, part of the British Army, that served in the First World War and remained in the United Kingdom throughout the Second World War.

The 143rd Infantry Brigade was an infantry brigade of the British Army that saw active service in both the First and the Second World Wars. In the First World War the brigade served on both Western Front and later the Italian Front. During the Second World War the brigade fought in Belgium and France before being evacuated to England where it remained for the rest of the war and was finally disbanded in 1946. Raised again in the 1980s, this brigade disbanded under Army 2020 in November 2014.

The 145th Infantry Brigade was a regional brigade of the British Army that saw active service in both the First and the Second World Wars, disbanding in 1943 and being reformed in the 1990s. The Brigade was renamed Headquarters 11th Infantry Brigade and Headquarters South East in October 2014.

The 146th Infantry Brigade was an infantry brigade formation of the British Army, part of the Territorial Force with the 49th Infantry Division. The brigade saw active service during both the First and the Second World Wars, and during the early part of the Cold War. The brigade was active from 1908 until 1967 when it was finally disbanded. The brigade was reformed in 1983, though with a much smaller and insignificant role before finally disbanding again in 1993.

The 147th Infantry Brigade was an infantry brigade of the British Army, part of the Territorial Force, that served in both the First and the Second World Wars with the 49th Infantry Division.

The 148th Infantry Brigade was an infantry brigade formation of the British Army that served in both the First and briefly in the Second World War as part of the 49th Infantry Division and disbanded after the war.

The 153rd Infantry Brigade, part of the 51st (Highland) Infantry Division, was an infantry brigade of the British Army that fought during both the First and Second world wars. It was raised in 1908, as the 2nd Highland Brigade, upon the creation of the Territorial Force and was later redesignated the 153rd Brigade.

The 154th Infantry Brigade was an infantry brigade of the British Army division that fought during both the First and Second world wars. The brigade was raised in 1908, upon the creation of the Territorial Force, as the Argyll and Sutherland Brigade and was later redesignated as the 154th Brigade. The division was referred to as the "Highway Decorators" by other divisions who became used to discovering the 'HD' insignia painted wherever the Highlanders had passed through.

160 (Welsh) Brigade or Brigâd 160 (Cymru), previously 160 Infantry Brigade and Headquarters Wales, is a regional brigade of the British Army that has been in existence since 1908, and saw service during both the First and the Second World Wars, as part of the 53rd (Welsh) Infantry Division. It is a regional command responsible for all of Wales. The Brigade is also regionally aligned with the Eastern European and Central Asian regions as part of defence engagement. The brigade organises an annual patrolling competition in the Brecon Beacons, known as Exercise Cambrian Patrol.

The 212th Brigade was a Home Service formation of the British Army during the First and the Second World Wars.

The 218th Brigade was a Home Service formation of the British Army during the First and the Second World Wars.

The 219th Brigade was a Home Service formation of the British Army during the First and the Second World Wars.

The 223rd Brigade was a Home Defence formation of the British Army in the First and the Second World Wars. It existed under several variations of the 223 Brigade title, and was eventually converted into an airborne formation.

The 231st Brigade was an infantry brigade of the British Army that saw active service in both the First and the Second World Wars. In each case it was formed by redesignation of existing formations. In the First World War, it fought in Palestine and on the Western Front, while during the Second World War it served in the Allied invasion of Sicily, Italy and the Normandy landings of 6 June 1944.