Could attacking Australia knock Britain out of the war?

Could a Japanese attack on Australia knock Britain or Australia out of the war?

Probably not; it would more likely enrage Australia and impose severe additional strain on Britain's worldwide commitments.

The viewer asks whether the added Far Eastern crisis could remove Britain from the war. Britain would remain in the conflict, and Australia would also be unlikely to leave after being attacked. An assault on Australian territory would produce anger and resistance rather than accommodation. The strategic effect would instead be heavier strain on British shipping, forces, and production as Churchill tried to support a core imperial partner while continuing the war elsewhere.