After the fall of Singapore the Australian Government and many Australians feared that Japan would invade the Australian mainland. Australia was ill-prepared to counter such an attack as the RAAF lacked modern aircraft and the RAN was too small and unbalanced to counter the Imperial Japanese Navy. Additionally, the Army, although large, contained many inexperienced units and lacked mobility. In response to this threat most of the AIF was brought back from the Middle East and the Government appealed to the United States for assistance. British Prime Minister Winston Churchill attempted to divert the 6th and 7th Divisions to Burma while they were en route to Australia, but Curtin refused to authorise this movement. As a compromise two brigades of the 6th Division disembarked at Ceylon and formed part of the island's garrison until they returned to Australia in August 1942.