AUKUS navy chiefs have declared they have to be ready to fight and win a war to protect “unfettered access” to the high seas for trade and the international rules-based order being threatened by China, Russia and Iran.

Issuing a stark warning about the deteriorating geostrategic environment, the chiefs of the Australian, US and British navies on Wednesday stressed the importance of Australia getting nuclear-powered submarines to deterring military adventurism by the Western allies’ potential foes.