If the Brits didn't occupy Australia then it would have been taken by the French. Then when the Japs took Singapore in WWII the froggies would have turned tail and run. Once the Japs had walked into Australia they would have been hard to shift even with nuclear weapons. Hirohito's henchmen would still control China, Eastern Asia, the Western Pacific and in a worst case scenario they might have even taken over a war weakened Europe.
