Army Group Royal Artillery

An Army Group Royal Artillery (AGRA) was a British Commonwealth military formation during the Second World War and shortly thereafter. Generally assigned to Army corps, an AGRA provided the medium and heavy artillery to higher formations within the British Army.
Background.
The First World War had been the first artillery war, in which the British Royal Artillery (RA) advanced enormously in technological and tactical sophistication. Independent Heavy and Siege batteries of the Royal Garrison Artillery (RGA) were grouped into Heavy Artillery Groups, later termed brigades, under the command of a lieutenant-colonel, at the disposal of Army Corps. Despite much debate, no higher organisational command structure was evolved.
By the time of the Second World War, the RGA had been integrated into RA and brigades of heavy and siege guns had become regiments of medium and heavy artillery, with more modern equipment. There was still an absence of a higher command structure and a need for one, for the central control of artillery above the division, had become apparent to the British Expeditionary Force during the Battle of France in 1940 and in the early part of the Western Desert Campaign.
Concept.
The AGRA concept was developed during Exercise Bumper held in the UK in 1941, organised by General Alan Brooke (a gunner), the commander of Home Forces, with Lieutenant-General Bernard Montgomery as chief umpire. This large anti-invasion exercise tested many of the tactical concepts that would be used by the British Army in the latter stages of the war. The RA developed what became the AGRA, a powerful artillery brigade, usually comprising three medium regiments and one field regiment, which could dominate the battlefield and have the fire power for counter-battery bombardments.
AGRAs were improvised until 26 November 1942, when they were officially sanctioned, to consist of a commander and staff to control non-divisional artillery.
Service.
AGRAs made their debut with First Army in the Mediterranean Theatre of Operations and the concept was adopted during the and Far East campaigns.
An AGRA usually had three medium artillery regiments, one heavy artillery regiment and one field artillery regiment. It was commanded by a brigadier and was transferred at need from corps to corps within an army. Each corps in the line usually had an AGRA and when especially heavy fire support was needed, one AGRA could be used to reinforce another, as in Operation Baytown, the initial attack on the Italian mainland, when two AGRAs fired across the Straits of Messina from Sicily or in Operation Undergo, the battle for Calais in 1944. As the British Army manpower shortage developed, the weight of fire that an AGRA could add to an attack became increasingly important.
AGRAs were not originally provided with their own Royal Electrical and Mechanical Engineers (REME) workshops, and experience proved that this was a mistake in theatres with limited support services, such as the Italian Front. Switching large groupings of artillery from one corps to another put immense strain on the corps' own REME, and later the AGRAs in Italy were provided with their own workshops, though not specifically attached to any particular AGRA.
Commonwealth AGRAs.
Canadian corps artillery was also referred to as an AGRA and was composed of units of the Royal Canadian Artillery as well as the Royal Artillery. Canada had two AGRAs in the Second World War, one in Italy as part of I Canadian Corps and North West Europe from March 1945 and the other only in North West Europe with II Canadian Corps.
After the war, 59th AGRA appears to have been transferred to the British Indian Army in 1946, becoming 59 Army Group Royal Indian Artillery, retitled 2 Army Group RIA the following year. At Independence in 1947, the order of battle of the RIA included 1 AGRIA, 2 AGRIA and 11 AGRIA (AA).
List of AGRAs during the Second World War.
Where known, with area of operation and dates formed and disbanded.
List of postwar AGRAs.
After the Second World War, AGRAs were mainly used to control Territorial Army (TA) units, particularly AA units that did not form part of Anti-Aircraft Command. Later, a few were created in the regular Army for the British Army of the Rhine (BAOR).