“We are now sending IHI engineers to Rolls-Royce and they are sending engineers to us in Japan,” said Sato. “There are a lot of new technologies that need to be validated. Another priority is the design of the engine to ensure it can be integrated into the new fighter aircraft.”

He said the two companies aim to develop an engine prototype by the late 2020s to enable integration into the initial batches of GCAP fighters to be produced from the mid-2030s. Initial tests of the engine will take place in the UK, he said.