The US is sharing a once highly-guarded missile system that will make British and Australian nuclear submarines far more deadly

Sidharth Kaushal, an analyst at London's Royal United Services Institute, said that technology gives the submarines the capacity to fire hypersonic missiles, which can evade defense systems. "Hypersonic missiles are important as they have the speed and range to penetrate defended airspace and hit hardened targets," he told Insider. "For nations which do not have stealth bombers (everyone excluding the US) they may represent the only way of striking targets at reach within well defended enemy airspace."