Upon its formation the 1st Armoured Division was organised along British lines and was authorised six armoured regiments and an armoured car regiment. While these regiments began forming in mid-1941 they were not issued with any tanks as it was planned to equip the division and finalise its training when it deployed to the Middle East between December 1941 and March 1942. Following the outbreak of war in the Pacific the decision was made to retain the division in Australia. At this stage, there were still not enough tanks available to complete the division's equipment requirements, and so as an interim solution the division's armoured regiments were equipped with Bren Carriers until sufficient tanks arrived. These were replaced by newly arrived M3 Grant medium tanks in April and May 1942, and the division completed its training in northern New South Wales, before moving to Western Australia in 1943 where it was tasked with defending against a possible Japanese invasion.