In addition to the armoured brigades assigned to a division, the British Army utilised several brigades that operated as independent formations. In the early stages of the war, this could range from being assigned to provide armour support to an expeditionary force, such as the 1st Armoured Brigade during the Battle of Greece, to being used for independent tasks such as the 9th Armoured Brigade during the Second Battle of El Alamein. During the Western Desert Campaign, the main function of these independent formations was to replace brigades within a division that had suffered heavy losses; to reinforce an armoured division to increase its tank strength temporarily; or to provide tank support to infantry formations by being temporarily assigned to them. These formations were also to be structured the same way as those brigades assigned to armoured divisions. In preparation for the Allied invasion of France in 1944, the British Army intended to prepare eight tank brigades to provide infantry support. These brigades were to be assigned to corps or army level commands, and then allocated to infantry divisions as needed. As tank production could not meet the numbers required, five of these brigades were organised as independent armoured brigades and equipped with M4 Shermans. General Bernard Montgomery, commander of the 21st Army Group to which these brigades were assigned, had advocated for a Universal Tank that combined the aspects of the infantry and cruiser tanks. In the interim, he believed that the M4 Sherman was the closest tool for the universal tank role. He made clear that he saw no distinction between armoured and tank brigades, and would use either as he saw fit and not via the previously defined roles that they had been given. The lack of enforced doctrine allowed these armoured brigades to implement infantry support as they saw fit.