Japan Shows Its Colours on Next-Generation Combat Aircraft Collaboration

Flying in tandem: Japan is reportedly nearing a deal to work with the UK on the next-generation Tempest aircraft, a prototype of which is shown here. Image: Defence Imagery / MOD News Licence

As reports suggest that Japan is preparing to join the UK and Italy in developing a future generation of fighter aircraft, what can be expected from such an arrangement?

Tokyo’s Nikkei newspaper has reported that Japan is near agreement with the UK and Italy on the joint development of a future fighter, which would be a radical departure for each of the countries in terms of defence collaboration. Historically the UK has worked with continental European countries on combat aircraft development, whereas Japan has sought access to US technology through licensed production (the F-15) or joint development (the F-2).

If this report is accurate, it would constitute a significant advance on the current situation, in which the four leading companies on Tempest (BAE Systems, Rolls Royce, Leonardo and MBDA) have been discussing cooperation on the airframe and sub-systems with their Japanese equivalents.

It is conceivable that the Japanese government has leaked news of the imminence of a merging of two aircraft programmes (the F-X and Tempest) to test the water as regards Japanese public opinion, perhaps because the reported agreement with the UK and Italy is linked to Japan’s readiness to modify its arms export practices. For its part, the UK government has been cautious about speaking on the possible merging of the two programmes (as opposed to sub-system collaboration for two different aircraft). This is to avoid any appearance of taking the Japanese government for granted, and also because it did not wish to give the impression that the Tempest programme would not be viable without Japanese involvement.

An agreement on the joint development of an expensive and key defence platform would represent a major step-up in the intensity of UK–Italy–Japan defence relations, but would rest on a developing foundation of related and enabling agreements. The wider context is one of growing Japan–UK interest in defence and security cooperation dating back to agreements on arms exports and information security in 2013, which were reinforced by the 2017 Joint Declaration on Security and Defence Cooperation. The 2017 agreement on logistics cooperation facilitated the subsequent visits of both HMS Queen Elizabeth and Typhoon aircraft to Japan. Earlier this year, the two countries concluded a Reciprocal Access Agreement to facilitate the entry and regulation of visiting troops. A further useful aspect in support of cooperation is that each of the parties cite the same desired in-service date of 2035 for a new combat aircraft. Overall, the past decade has given Japan the opportunity to learn about the behaviours and practices needed to make equipment collaboration work smoothly.

The importance of the project for the wider relationship between the partners should be profound

Clearly, the implementation of an ambitious aircraft project would be far from straightforward, given the range of capabilities that would likely need to be developed and integrated. There will be many organisational, decision-making and information security matters to be settled, with this project needing to improve on the management arrangements used for Typhoon and Tornado. However, with three partners, the project will have a stronger financial and political foundation.

A defined requirement has (wisely) not been set. It will depend on the rate of technology advances in the next three or four years, the changing threat situation, and likely costs and budget availability. A key characteristic on the UK side is that the Ministry of Defence has been working closely with selected industry rather than relying on competitive pressures to minimise the chances of a ‘conspiracy of optimism’ regarding performance and cost. Should a single collaborative programme emerge, this approach is likely to continue, not least because the Japanese government is using a similar ‘national champion’ set of firms in the defence field. Throughout the programme, it will be important to keep Italian government and industry onboard as a junior but respected and valued partner, which should be eased by Leonardo being a key player in the UK and Italian industrial sectors.

A remaining unknown is whether the trilateral project will encounter active opposition from the US. Japan did give the US and Lockheed Martin the first opportunity to be its project partner on the F-X, but reportedly did not receive the technology transfer assurances that would have given Japan the operational independence it seeks. Also, the US appears to be focused on an F-22 replacement, which would be more expensive than anything that Japan or the UK could contemplate. To date, there has been no sign of US pressure on Japan to alter its apparent partner of choice, but this could change, especially with a different administration in Washington.

The importance of the project for the wider relationship between the partners should be profound. It will generate an extensive network of contacts between governments and industrial figures that will be in place for more than 30 years.

A formal Japanese choice should emerge shortly with the publication of the major reviews that were launched in 2021, and which are due by the end of this year.

The views expressed in this Commentary are the author’s, and do not represent those of RUSI or any other institution.

Have an idea for a Commentary you’d like to write for us? Send a short pitch to commentaries@rusi.org and we’ll get back to you if it fits into our research interests. Full guidelines for contributors can be found here.


Trevor Taylor

Professorial Research Fellow

Defence, Industries and Society

View profile


Explore our related content