force for service overseas during the war. This decision was based upon the provisions of the Defence Act (1903) which precluded sending members of the Militia outside of Australian territory to fight. Meanwhile, the Militia was tasked with home defence, and the 3rd Brigade was assigned a command reserve role within Southern Command. At this time, units of the Militia were called upon to undertake defensive duties and to provide training for men that were called up for national service following the recommencement of the compulsory training scheme in January 1940. Initially this was undertaken in small blocks of continuous training, however, following Japan's entry into the war following the bombing of Pearl Harbor and the invasion of Malaya in December 1941, the 3rd Brigade was mobilised for wartime service. Following this the brigade, consisting of the 10th, 27th, 43rd and 48th Battalions, was attached to the Northern Territory Force and sent to Darwin to defend the port against a possible Japanese invasion. Initially, only the 27th and 43rd Battalions were sent to Darwin, while the 3rd Brigade headquarters and 48th Battalion remained in Adelaide, and the 10th Battalion joined the Adelaide Covering Force. In early1943, brigade headquarters deployed north, and the 48th Battalion was transferred to Victoria to join the 6th Brigade. In March 1943, as the threat of invasion diminished, the brigade was re-allocated to the 4th Division and was withdrawn to Adelaide, before moving to Queensland in July 1944. Here, the brigade concentrated around Townsville, assuming a defensive role across an area that stretched as far as Cape York. The brigade subsequently became a direct command unit of the First Army, and was bolstered with the 6th Field Regiment and the 1st Independent Light Horse Squadron. The 27th Battalion was later transferred to the 23rd Brigade, but was replaced by the 62nd Battalion following its return from Merauke. The brigade was disbanded in April 1944, as part of the reduction of Australian forces that had begun in late 1942 in an effort to release manpower back into the Australian economy. Upon disbandment, the brigade consisted of two infantry battalions, the 55th/53rd and the 62nd Battalions. While the 62nd Battalion was disbanded at this time, along with the 3rd Brigade's headquarters, the 55th/53rd Battalion remained in existence as a direct command unit of the First Army. Post-war deployments When Australia's military began reforming in 1948, the brigade was