Lacking air protection, Sarawak, together with rest of the island, fell to the Japanese and Vyner took sanctuary in Australia. Many of the British and Australian soldiers captured after the fall of Malaya and Singapore were brought to Borneo and held as prisoners of war (POWs) in Batu Lintang camp in Sarawak and Sandakan camp in neighbouring North Borneo. The Japanese military authorities placed the southern part of Borneo under the navy, while its army were responsible for management of the north. As part of the Allied Campaign to retake their possessions in the East, Allied forces were then sent to Borneo in the Borneo Campaign and liberated the island. The Australian Imperial Force (AIF) played a significant role in the mission. The Allies' Z Special Unit provided intelligence gathering which facilitated the AIF landings. Most of the major towns of Sarawak were bombed during this period. The war ended on 15 August 1945 following the Japanese surrender and the administration of Sarawak was undertaken by the British Military Administration (BMA) from September. Vyner returned to administer Sarawak but decided to cede it to the British government as a Crown Colony on 1 July 1946 due to lack of resources to finance reconstruction.