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 the RA, and brigades of heavy and siege guns became 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 North West Europe 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