The UK’s nuclear-powered submarine fleet could double in size as plans were revealed for the new “Aukus” vessels to be based on a British design. In a bid to counter the growing threat from China, the UK’s prime minister, Rishi Sunak, vowed alongside his US and Australian counterparts to stand “shoulder to shoulder” to protect peace in the Indo-Pacific given its implications for security across the world. A “historic” deal 18 months in the making was announced by the three leaders in Point Loma, San Diego, that will see new…