Regiment" and they were once again assigned to the 15th Brigade, which was part of the 3rd Division of the Second Australian Imperial Force. World War 2 At the outset of the Second World War, initial operations were conceived to be likely in the Middle East, France and later possibly the United Kingdom. Due to the provisions of the Defence Act (1903) which prohibited sending the Militia to fight outside of Australian territory, the decision was made to raise an all volunteer force to serve overseas while the Militia would be used to defend the Australian mainland and to improve Australia's overall level of readiness through the re-institution of compulsory military service and extended periods of continuous training. The diplomatic entry of Japan into the war in 1940, however, having signed the Axis Tripartite Pact in September of that year, posed a heightened potential threat to the Australian mainland. As a result, the under-prepared Australian military began to mobilise for likely war in the South West Pacific. The Militia was called up for full-time service to undertake defensive duties on the Australian continental mainland and in the Australian territory of New Guinea. For its part, the 57th/60th Battalion conducted a number of training camps during 1940 and into 1941 at Mount Martha before moving camp northwards to Trawool and Seymour in central Victoria early in 1942. Japan officially entered the war on 7 December 1941 with coordinated attacks upon Hong Kong, Guam, Pearl Harbor, Wake Island, the Philippines and other allied-occupied strategic targets in the Pacific. The Bombing of Darwin in February 1942 only served to heighten concerns that an invasion of the Australian mainland was possible, the event serving to focus the minds of the Australian military. A few months later, in March and April 1942, the 57th/60th Battalion along with the rest of the Australian 15th Brigade was relocated to New South Wales where they were given the task of defending the Tweed Valley in case of Japanese invasion. As a major fitness and training exercise the battalion was route marched from Seymour to Albury (217 km), whereupon they took a train to the town of Casino, New South Wales. The part played by the 57th/60th in the defence of the mainland was to conduct a lengthy bivouac in the area just north of Casino. Later in the year, in September 1942, the 15th Brigade was released from