World War I
World War II
Cold War 1951-1994
|The Prince of
Sir Douglas Haig
Sir Charles Monro
Sir Hubert Gough
Sir Arthur Holland
Sir John Dill
Sir Harold Alexander
I Corps was an army corps in existence as an active formation in the British Army for most of the 80 years from its creation in World War I until the end of the Cold War, longer than any other corps. It had a short-lived precursor during the Waterloo Campaign.
Assembling an army in Belgium to fight Napoleon’s resurgent forces in the spring of 1815, the Duke of Wellington formed it into army corps, deliberately mixing units from the Anglo-Hanoverian, Dutch-Belgian and German contingents so that the weaker elements would be stiffened by more experienced or reliable troops. A he put it: ‘It was necessary to organize these troops in brigades, divisions, and corps d’armee with those better disciplined and more accustomed to war’. He placed I Corps under the command of the Prince of Orange and it was this corps that was first contacted by the advancing French at Quatre Bras on 16 June 1815. However, Wellington did not employ the corps as tactical entities, and continued his accustomed practice of issuing orders directly to divisional and lower commanders. When he drew up his army on the ridge at Waterloo, elements of the various corps were mixed up, and although he gave the Prince of Orange nominal command of the centre, that officer had different forces under him. Subsequent to the battle, the corps structure was re-established for the advance into France, I Corps being commanded by Maj-Gen Sir John Byng, the Prince of Orange having been wounded at Waterloo.
After Waterloo the army corps structure largely disappeared from the British Army, except for ad hoc formations assembled during annual manoeuvres (eg Army Manoeuvres of 1913). In 1876 a Mobilisation Scheme for eight army corps was published, with '1st Corps' based on Colchester. This scheme had been dropped by 1881. The Stanhope Memorandum of 1891 (drawn up by Edward Stanhope when Secretary of State for War) laid down the policy that after providing for garrisons and India, the army should be able to mobilise three army corps for home defence, two of regular troops and one partly of militia, each of three divisions. Only after those commitments, it was hoped, might two army corps be organised for the unlikely eventuality of deployment abroad. The 1901 Army Estimates introduced by St John Brodrick allowed for six army corps based on the six regional commands (Aldershot, Southern, Irish , Eastern, Northern and Scottish) of which only I Corps (Aldershot Command) and II Corps (Southern Command on Salisbury Plain) would be entirely formed of regular troops. However, these arrangements remained theoretical, the title 'I Corps' being added to Aldershot Command. In 1907 the title changed to 'Aldershot Corps' and reverted to simply 'Aldershot Command' the following year. Finally, the Haldane Reforms of 1907 established a six-division British Expeditionary Force for deployment overseas, but only Aldershot Command possessed two infantry divisions and a full complement of ‘army troops’ to form an army corps in the field.
Pre-war planning for the British Expeditionary Force (BEF) did not envisage any intermediate headquarters between GHQ and the six infantry divisions, but it was assumed that if corps HQs became necessary, then the GOC Aldershot Command would automatically become GOC I Corps in the field. On mobilisation in August 1914 the decision was made to conform to the two-division army corps organisation employed by the French armies alongside which the BEF was to operate. Sir Douglas Haig, then commanding at Aldershot, therefore took I Corps HQ to France with 1st Division and 2nd Division under command, and it remained on the Western Front throughout the war. It had a peripheral part at the Battle of Mons, then saw hard fighting at the Battle of the Aisne and First Battle of Ypres in 1914, at the Battle of Aubers Ridge in the Spring of 1915 and alongside the Canadian Corps at the Battle of Hill 70, as well in many other large battles of World War I.
The composition of army corps changed frequently. Some representative orders of battle for I Corps are given here.
Order of Battle at Mons 23 August 1914
By the time of the battles of Aubers Ridge and Festubert (May 1915), I Corps still had 1st and 2nd Divisions under command, but had been reinforced by 47th (1/2nd London) Division of the Territorial Force, and 1st Canadian Division. Once the era of trench warfare had set in on the Western Front (1915–17), the BEF left its army corps in position for long periods, so that they became familiar with their sector, while rotating divisions as they required rest, training, or transfer to other sectors.
Sir Arthur Holland
BGGS: Brig-Gen G.V. Hordern
Deputy Adjutant & Quartermaster-General: Brig-Gen N.G. Anderson
Commander, Royal Artillery: Brig-Gen H.C. Sheppard
Commander, Heavy Artillery: Brig-Gen F.G. Maunsell
Commander, Engineers: Brig-Gen H.W. Gordon
During World War II, I Corps' first assignment was again to the British Expeditionary Force where it was commanded by General Dill, and then Lieut-Gen Barker from April 1940. After the Germans broke through Allied lines in May 1940, the BEF was forced to retreat to Dunkirk for evacuation. The GOCinC, Lord Gort, ordered Barker to form the rearguard with I Corps to cover the evacuation, and surrender to the Germans as a last resort. However, the acting commander of II Corps, Maj-Gen Bernard Montgomery, advised Gort that Barker was in an unfit state to be left in final command, and recommended that Maj-Gen Harold Alexander of 1st Division should be put in charge. Gort did as Montgomery advised, and in the event the bulk of I Corps was successfully evacuated. As Montgomery recalled: '"Alex" got everyone away in his own calm and confident manner'.
GOC: Lt-Gen M.G.H. Barker
I Corps then remained in the United Kingdom until the landings in Normandy for Operation Overlord, where, along with XXX Corps, it was a spearhead corps of Second Army of 21st Army Group. After fighting for two months around Caen, the Corps was subordinated on 1 August 1944 to First Canadian Army for the remainder of the Normandy campaign  and the subsequent operations in the Low Countries and Germany until 1 April 1945. I Corps Headquarters then took over administration of 21st Army Group's logistics area around the port of Antwerp, Belgium until the end of the war. During the North-West Europe campaign it was under the command of Lieutenant General John Crocker.
GOC: Lt-Gen John Crocker
Assignments of corps to armies, and divisions to corps, changed frequently during the campaign:
As of 6 June 1944
As of 7 July 1944
As of 1 August 1944 (now part of First Canadian Army)
After the defeat of Germany, 21st Army Group became the British Army of the Rhine (BAOR), and I Corps was transformed into a corps district, with an administrative, rather than combat, role. It was disbanded in 1947.
However, in October 1951 the corps was reactivated to become the principal combat element of the BAOR, with its HQ based in Bielefeld. In March 1952, following the reactivation of 6th Armoured Division, its component formations were:
Included as part of this was Canada's contribution to the NATO land forces in Germany. A Canadian mechanised brigade remained part of BAOR until 1970.
In a following 1958-60 reorganisation the Corps was formed into three mixed armour/infantry divisions including five brigade groups, which were in 1965 brought together into three centralised divisions. With the end of National Service manpower across the whole of BAOR dropped from around 77,000 to 55,000.
In the late 1970s the Corps was reorganised as four small five battle group armoured divisions plus a roughly brigade sized infantry 'Field Force'. It then comprised:
Following the 1981-3 reorganisation, the Corps consisted of 1st and 4th Armoured Divisions, which would have manned the front line against the anticipated attack by the Soviet 3rd Shock Army, plus in an in-depth, reserve role the 3rd Armoured Division and finally the 2nd Infantry Division which was tasked with rear-area security.
With the end of the Cold War, I (BR) Corps was redesignated in 1992 as a NATO Rapid Reaction Corps under SACEUR and renamed as Headquarters Allied Command Europe Rapid Reaction Corps. HQ ARRC moved to Rheindahlen in 1994.
This list is incomplete
(Note: 1 Corps was disbanded in June 1947 and reformed in late 1951)