Sept 3 — The visit of UK Defence Secretary John Healey to Tokyo, alongside the Royal Navy’s flagship HMS Prince of Wales, marked a historic moment for UK–Japan defence ties. Not only was it the first time a British aircraft carrier docked in the Japanese capital, but it also featured a landmark exercise where an RAF F-35B Lightning II jet landed on the Japan Maritime Self-Defense Force (JMSDF) JS Kaga.
Although officially a destroyer, the JS Kaga is always viewed by experts as a de facto aircraft carrier.
In this event, both the UK and Japan reaffirmed their shared commitment to technological innovation, interoperability, and upholding the rules-based international order. Both also expressed strong commitment to deepening strategic security alignment across the Indo-Pacific and Euro-Atlantic regions.
A central pillar of this growing partnership is the Reciprocal Access Agreement (RAA) signed between the UK and Japan in 2023. The UK is the first in Europe to conclude such a defence pact with Japan.
The agreement streamlines procedures for the deployment of forces, equipment, and joint exercises in each other’s territories, significantly reducing bureaucratic issues and legal barriers that limit conventional defence cooperation, thereby facilitating more frequent and complex military engagements. For Japan, it is a step towards expanding its network beyond its alliance with the United States.
People take photographs of British aircraft carrier HMS Prince of Wales arriving at Tokyo Bay August 28, 2025. — AFP pic
In fact, the UK was not the first country to sign an RAA with Japan — it originated with Australia, signed by Tokyo in January 2022. This RAA was rooted in shared strategic concerns across the regions of Indochina and the Western Pacific. Reflecting this commitment, the Japan Ground Self-Defense Force (JGSDF) regularly participates in military drills in the Indo-Pacific region, especially in Australia. In Exercise Talisman Sabre this year, the JGSDF conducted a live-fire demonstration of its Type 12 surface-to-ship missiles off Jervis Bay, successfully striking sea targets in a coordinated display with Australian forces.
Beginning this year, Japan will rotate elements of its Amphibious Rapid Deployment Brigade during Talisman Sabre exercises — around 600 troops during exercise years, and approximately 100 in non-exercise years. These sustained deployments not only strengthen interoperability but also symbolise Japan’s forward operational posture alongside Australia and the United States.
While Japan–Australia cooperation is focusing on interoperability and joint capability, Japan–UK defence collaboration is further rooted in high-tech cooperation. The Global Combat Air Programme (GCAP), for example, is an effort to develop a sixth-generation fighter jet involving Italy as well. Both countries are also exploring further military technology development in areas such as maritime systems, cyber security, and space technology.
The Five Power Defence Arrangements (FPDA) was originally designed to protect Malaysia and Singapore through the commitment of the United Kingdom, Australia, and New Zealand. With increasingly complex geopolitics, it is time to raise the question of whether Japan should be included as an additional partner.
Several factors support this proposition.
First, the geographical logic is compelling. Japan’s proximity to Southeast Asia means that any developments in the South China Sea and surrounding sea lanes have a direct impact on its national security and economic lifelines. The original purpose of the FPDA could be enhanced by participation from Japan, since Tokyo has a vested interest in preserving freedom of navigation and regional stability in nearby waters.
Secondly, Japan’s political and economic interests in Asean align strongly with the objectives of the FPDA. Japan is one of the largest investors and trading partners for Asean, with energy imports and manufacturing supply chains relying heavily on the security of maritime routes through the Malacca Strait and South China Sea. Integration of Japan into the FPDA would therefore not only reinforce collective defence but also anchor the role of Asean in broader Indo-Pacific security.
Third, Japan’s RAAs with both the UK and Australia, as well as its growing security cooperation with Singapore and Malaysia, provide a natural bridge for institutionalising its participation. Formalising this within the FPDA would transform these existing bilateral links into a more structured, multilateral defence framework.
Last but not least, is Japan’s defence technological level. The FPDA members field a diverse range of military platforms that could complement one another in joint operations.
For example, the FPDA and Japan could conduct one of the most advanced anti-submarine warfare (ASW) exercises in the world, leveraging a full spectrum of capabilities across air, surface, and sub-surface domains.
Imagine a future ASW exercise: long-range P-8A Poseidon Maritime Patrol Aircraft (MPA) operated by Australian and UK forces detect the presence of a submarine, followed by Merlin HM2 helicopters embarked on Royal Navy Type 23 frigates, Super Lynx helicopters deployed from Lekiu-class frigates of the Royal Malaysian Navy, and S-70B Seahawks from Formidable-class frigates of the Republic of Singapore Navy closing in and deploying dipping sonar. On the surface, Asahi-class and Mogami-class destroyers from the JMSDF could work alongside Singapore’s Formidable-class frigates, New Zealand’s ANZAC-class, and the UK’s Type 23 to deliver layered coverage.
Such comprehensive and multi-layered drills would sharpen detection, tracking, and engagement skills of all forces involved, providing invaluable joint undersea warfare experience and reinforcing the credibility of the FPDA as a modern, advanced, and adaptable security arrangement.
In addition, it would be meaningful to see HMS Prince of Wales sailing together with an Izumo-class destroyer as a combined strike group, supported by Hobart-class destroyers and Canberra-class amphibious assault ships from the Royal Australian Navy, as well as vessels from Singapore and Malaysia. Such integration would not only strengthen maritime presence but also allow the FPDA to train for high-end combined operations.
In the air domain, Japan and the UK are operating F-35Bs on HMS Prince of Wales and JS Kaga respectively, while Australia and Singapore are transitioning to the F-35A soon. Although different variants, they still offer opportunities to deepen interoperability through shared training and tactics in fifth-generation air combat.
On the other hand, one of the non-conventional operations mentioned in the FPDA five-year roadmap is drones/unmanned vehicles.
While the FPDA and Japan differ in their approaches to drones/unmanned systems, both possess complementary strengths that can enhance regional stability. The FPDA has begun integrating drones and unmanned vehicles into joint military exercises primarily for surveillance, maritime security, and humanitarian operations. Australia and the UK can contribute advanced ISR platforms, while Singapore is expanding its tactical drone capabilities. Meanwhile, Japan has developed a diversified unmanned systems portfolio through significant investment and strategic planning, including shipborne VTOL drones, high-altitude surveillance UAVs, and autonomous surface vehicles. Japan’s emphasis on AI-enabled platforms, counter-drone technologies, and logistics UAVs positions it as a technological leader in the region.
By aligning Japan’s advanced capabilities with the FPDA’s operational framework, there is potential to create a more resilient and dynamic regional security architecture that leverages the FPDA’s cooperative model and Japan’s innovation.
In conclusion, the formation of “FPDA+Japan” could significantly enhance regional stability and provide tangible benefits for all members. A stronger, more networked FPDA–Japan partnership would improve interoperability, readiness, and collective deterrence in an increasingly contested maritime region in the Indo-Pacific.
However, it is equally important to note that the fundamental principle of the FPDA is that it is a neutral defence arrangement. The integration of Japan, while strategically valuable, must be handled cautiously to avoid misinterpretation by China, where anti-Japan sentiment remains sensitive. Hence, striking a balance between capability enhancement and diplomatic neutrality will be essential for the sustainable effectiveness of the FPDA.
* Phar Kim Beng, PhD is the Professor of Asean Studies at International Islamic University of Malaysia and Director of Institute of Internationalisation and Asean Studies (IINTAS). Jitkai Chin, PhD PEng, is part of the Department of Chemical Engineering at Universiti Teknologi Petronas.
** This is the personal opinion of the writer or publication and does not necessarily represent the views of Malay Mail.
