It sounds like something out of a Hollywood movie: a fighter jet set to take to the skies in 2035 equipped with hypersonic weapons capable of travelling at Mach 5, swarming drones controlled by artificial intelligence, and “directed energy” weapons that could use electromagnetic pulses to bring down enemy systems.

The plans are yet to be finalised, but the ambition is unprecedented. The jet would be at the centre of the first ever three-way defence collaboration between the UK, Japan and Italy, built on a design that would put it among the most sophisticated aircraft ever made.

Until now, Japan has worked exclusively with US partners on major military programmes. The tri-national project would merge Japan’s F-X programme with the UK and Italy’s Tempest project, marking a shift in the Asian country’s role in the global defence industry after years in the shadows.

The project would reinforce Tokyo’s determination to forge deeper security ties with a range of allies to prepare for the possibility of a war with China over Taiwan. “[It] will expand Japan’s network to Europe and contribute to strengthening its security environment, while potentially making exports possible,” says Katsutoshi Kawano, the former chief of Japan’s Self-Defense Forces’ Joint Staff.

By working with the UK, he adds, Japan would probably have more flexibility to upgrade its fighter jets to address growing security threats. “It’s unprecedented but I can’t really imagine a case…