Units & Formations 1930 - 1956:
Where two or more divisions were to be deployed on an operational basis, usually a corps level formation would be established to exercise command, control and coordination over the divisions allocated to it. Generally, corps formations were given specific geographic areas of operation, however, some corps formations were based upon function rather than location, for example I Airborne Corps (see attached pdf). The three anti-aircraft corps were both determined by function and location.
Prior to the outbreak of the Second World War, there were no corps in existence. However, the headquarters of Aldershot Command formed the nucleus of the ‘Spearhead’ Corps, which was to be the first corps level formation to be deployed overseas in the event of hostilities. Within Aldershot Command were located the 1 Infantry Division and 2 Infantry Division, which were to be the basis of that corps when it was mobilised. At the outbreak of the Second World War on the 3 September 1939, this is indeed what happened, with Headquarters I Corps being formed with effect from the 3 September to be deployed to France. As the British Expeditionary Force grew in strength, two additional corps headquarters were formed and deployed to France, namely II Corps and III Corps.
As is traditional with the British Army, as each new corps headquarters was raised, it was simply given the next consecutive numerical designation. So IV Corps was raised in February 1940, and although it was intended for deployment to France, it did not arrive prior to the German invasion and instead formed part of the forces deployed to Norway.
A group of new corps headquarters were formed in or around June 1940 with the evaucation of the British Expeditionary Force from France and threat of invasion looming large over the United Kingdom. V, VI, VII, VIII, X, XI and XII Corps were all formed in this period. IX Corps is an anomoly, logically it should have been formed around June 1940, but the first recorded account of its existence is April 1941.
All these corps headquarters were deployed in the United Kingdom. The first to be formed outside the U.K. was logically XIII Corps, formed in June 1940 by the redesignation of Western Desert Force. This was followed in September 1941 by the formation of XXX Corps, also in the Western Desert.
In the Far East, III Indian Corps was formed in April 1941 in Malaya. During the war, XV Indian Corps, XXXIII Indian Corps and XXXIV Corps were formed in India and served in Burma. XXI Indian Corps was formed for service in Persia and Iraq in 1942. Three anti-aircraft corps headquarters were formed for service in the U.K., and I Airborne Corps was formed in 1944 to assume command of the two British airborne divisions. There were also two Canadian corps headquarters deployed in Europe, and one Australian corps headquarters deployed in the Middle East. A New Zealand Corps existed for two specific operations in Tunisia and Italy.
Each corps was commanded by an officer of the rank of Lieutenant General (General Officer Commanding). Without exception, all were commanded by pre-war Regular Army officers of either the British Army or British Indian Army. The Canadian and Australian corps were commanded by officers from their own respective armies. For two period of times, once in Tunisia and once in Italy, a New Zealand Corps was formed under command of Lieutenant General FREYBERG, who was a British Army officer in the service of the New Zealand government.
The nationalities of the formations that served under a corps headquarters was not sacrosanct. The forces that served with X, XIII and XXX Corps in the Western Desert were from the U.K., India, Australia, New Zealand, South Africa, Poland, Free France and Czechoslavakia. In Burma and South East Asia, the British IV Corps and Indian XV and XXXIII Corps had both British, East African, West African and Indian formations under command. They were also commanded by both British (STOPFORD, CHRISTISON) and Indian (SLIM, SCOONES, MESSERVY and TUKER) Army officers without issue. I Burma Corps was formed in 1942 during the campaign in which the British were forced from Burma, to be disbanded when that campaign was concluded.
In Tunisia, two corps headquarters were sent from the U.K. as part of 1 Army (V Corps and IX Corps), with the latter being disbanded at the end of the campaign. XIII Corps and XXX Corps served in Sicily, with V Corps, X Corps and XIII Corps serving throughout the Italian campaign, together with I Canadian Corps. Headquarters III Corps and X Corps both served in Greece in late 1944 and early 1945, but with different designations.
I Corps and XXX Corps landed in Normandy on D-Day (6 June 1944), to be joined by VIII Corps, XII Corps and II Canadian Corps. These five corps formations fought throughout the campaign in North West Europe. Controversially, Headquarters I Airborne Corps landed at Nijmegan as part of Operation ‘Market Garden’.
The staff of a corps headquarters were drawn from all arms and services (see attached pdf). The chief staff officer to the General Officer Commanding held the rank of Brigadier (either acting or temporary) and was known as the Brigadier General Staff (B.G.S.). He was responsible for all operational aspects of the corps. The adjutant and quarter-master staff were headed by another Brigadier who held the appointment of Deputy Adjutant and Quarter-Master-General (D.A.Q.M.G.). There was a senior artillery, engineer and signals officer to head each of those arms within the corps. Likewise, a Deputy Director commanded the Royal Army Service Corps, Royal Army Medical Corps, Royal Army Ordnance Corps and (after 1942) the Royal Electrical and Mechanical Engineers services under command of the corps. Initially, these were Colonels appointments, but in 1944 they were upgraded to Brigadier appointments.