Rishi Sunak is poised to sign Britain’s biggest defence deal in decades – a multi-billion-pound submarine agreement with the US and Australia to counter China’s growing might in the Pacific.

In a summit this evening in San Diego, California alongside President Joe Biden and Australia’s Prime Minister, Anthony Albanese, Sunak will unveil the details of a plan to collaborate on building at least eight nuclear-powered submarines for the Australian navy by the 2040s. They’ll be designed by Britain, built in Australia, and use US technology and weapons.