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Reciprocity redefines the British-Japanese defence relationship

The Reciprocal Access Agreement (RAA) signed by Rishi Sunak and Fumio Kishda, prime ministers of the United Kingdom (UK) and Japan, respectively, on 11th January 2023 was described by His Majesty’s (HM) Government as ‘hugely significant for both nations’, even ‘the most important defence treaty between the UK and Japan since 1902’ (the founding year of the Anglo-Japan Alliance that lasted until the early 1920s). In simple terms, according to the Japanese Foreign Ministry, the RAA: 

…establishes procedures between Japan and the UK for the cooperative activities conducted by [the] defence force of one country while visiting the other country, and defines a status of the visiting force.

Attentive watchers of the UK-Japan relationship will be aware that British and Japanese forces have been exercising on each other’s territory since 2016, and so might question if this is such a major development. Indeed, the UK Parachute Regiment was on exercise in Japan the week before the agreement was signed. To grasp why the RAA deserves at least some of this fanfare requires looking beyond the administrative conveniences offered by a rather mundane legal instrument, and into its geopolitical context.

The view from London

The RAA is the latest gear change in a rapidly accelerating British-Japanese defence relationship. Consider just the last few months: November 2022 saw members of 1 Regiment Royal Horse Artillery, soldiers from 7 Para Royal Horse Artillery, 29 Commando Regiment Royal Artillery and 104 Regiment Royal Artillery take part in the bilateral exercise Vigilant Isles with Japanese troops in central Japan. Early December brought the much trailed announcement that the British, Japanese and Italian sixth generation warplane projects would merge into a ‘Global Combat Air System’. Also in December, the UK and Japan launched a digital partnership, increasing cooperation in semiconductors, cyber resilience and online safety. 

Britain is just the third country with which Japan has committed this level of military cooperation, after Australia (which also agreed a RAA last year) and the United States (which has a status of forces agreement). Being the first European country to have achieved such a ‘landmark’ agreement contributes to meeting an objective of the Integrated Review to ‘be the European partner with the broadest and most integrated presence in the Indo-Pacific’.

‘Global Britain’ and the ‘Indo-Pacific tilt’ are policies the British Prime Minister inherited from his predecessors. Sunak may have had another element of symbolism in mind when he invited his Japanese counterpart to the Tower of London to view the samurai armour Shogun Tokugawa Hidetada presented to King James to mark the first trade agreement between England and Japan in 1613. Common security and trade interests were prominent themes in Sunak’s comment piece on 12th January for Japan’s Nikkei newspaper:

We are committed to the security and stability of the Indo-Pacific region and we will work together to preserve our shared prosperity. There will be a strong degree of alignment as we publish an update to our own national security strategy this spring. 

Japan reciprocates the formula linking trade and security, as Hikariko Ono, Kishida’s press secretary, confirmed when she recently stated how the Comprehensive and Progressive Trans Pacific Partnership (CPTPP) that Japan will help Britain to join in 2023 is ‘not a mere trade agreement, but a strategic agreement’.

The view from Tokyo

The RAA should be seen in the context of Japan’s current strategy of improving its deterrent capability through an active and ambitious campaign that combines instruments of diplomacy and defence. This is driven by a perception in Tokyo that potential sources of danger surrounding Japan in the Indo-Pacific – from the Democratic People’s Republic of Korea, the People’s Republic of China, and Russia – are both compounding and combining. Kishida’s response is to promote the perception in countries key to the global security order that their safety from aggression is linked to Japan’s, and that implied solidarity – below the level of a formal alliance – helps deter aggression. This can be seen in the context into which the Japanese Foreign Ministry places the RAA: 

The international security environment is becoming more severe in various parts of the world, as the international order that has been established is challenged by Russia’s aggression against Ukraine and attempts to unilaterally change the status quo by force in the East and South China Seas. Against this backdrop, the Japan-UK security and defence cooperation will be lifted to new heights and the movement toward the realisation of a “free and open Indo-Pacific” will be further enhanced by the signing of this important security agreement between Japan and the UK, each other’s closest security partners in Asia and Europe.

As Daisuke Kawai, a Research Fellow at the Japan Institute of International Affairs, put it: ‘Expanding its military network is definitely one effective way to counter or try to deter China’. The UK may be at the front of the line in Europe, but the pattern is replicated more widely. During the week the RAA was signed, Japanese pilots were exercising with Indian air force pilots flying the same Russian made Sukhoi-30 type jets that the Japanese are used to intercepting in the airspace around their home islands. India may be joining the queue, but France or the Philippines could also be next in line for a RAA. 

It is in this context that the British desire for a more frequent presence of the UK’s military in and around Japan is reciprocated by Tokyo. For Britain, it serves to demonstrate the military substance of the ‘tilt’; for Japan, the goals of force modernisation (e.g. jointness), but also to signal to adversaries that it does not face them alone.

What difference does a RAA make?

According to the British Army’s website, ‘Military cooperation between the two countries is at its highest level since the Anglo-Japanese Alliance of 1902-1923’. So when it comes to ‘raising cooperation to the next level’ or ‘intensifying’ cooperation, what might result from the RAA? 

First, there are more incentives for a British military presence in Japan than for Japan to make deployments to Europe, so the outcome of this agreement in geographical terms may be less reciprocal than its name suggests. That might change, however, based on rising interest from Japan in closer cooperation with the North Atlantic Treaty Organisation (NATO). 

The RAA does offer an opportunity for the bilateral relationship to assume some of the qualities implied by a formal alliance.

Second, deployment of military personnel for ad hoc and short-notice activities is more likely to happen than had been the case when it entailed a disproportionately time-consuming diplomatic and administrative process. British and Japanese defence personnel (military and civilian) working alongside each other will become routine and normal. This increased range and frequency of contact will improve mutual familiarity and promote interoperability, which will be of incalculable value should a situation calling for operational support or combined operations arise. 

Although the most common assumption is that the RAA exists to support training, it could expand the UK’s operational footprint in the Indo-Pacific. This is implied by Sunak’s framing of two distinct results: 

…the signing today, which will rapidly accelerate defence and security cooperation and allow the UK and Japan to deploy forces in one another’s countries. It will also cement the UK’s commitment to Indo-Pacific security, allowing both forces to plan and deliver larger scale, more complex military exercises and deployments. 

That second element (exercises and deployments) leaves open the possibility of the agreement enabling British personnel to engage in operational as well as training activities. Mention of a ‘civilian component’ describing the personnel covered by the RAA may hint at expanded cooperation in other security areas, such as intelligence. These operational implications have not been overlooked in Beijing, as seen in a China Daily estimate that the RAA creates a legal basis for the deployment of British and Japanese troops on each other’s territory for training ‘and other operations.’

Whether for training, exercises or operations, this raises expectations that the British strategic establishment should be provided with the means not only to maintain but to increase the tempo and scope of deployments to the Indo-Pacific at a moment when defence budgets and strategy are under review.

What comes next?

The RAA will now be submitted for approval in both national parliaments. Some controversy has arisen over potential contradictions in each nation’s obligations with regard to criminal law, i.e., Japan has the death penalty, the UK does not. The notion that British personnel might be shielded from the ultimate sanction of Japanese law is somewhat reminiscent of the unequal treaties imposed by Europeans and Americans on Japan in the mid-19th century. Interestingly, a special (legally non-binding) note on discussions around the relevant article XXI of the agreement dealing with this contingency was published alongside the agreement and minutes of the discussion. Without Japan offering immunity, the possibility of granting certain waivers is mentioned, and the UK conditioned its obligation to assist an investigation on the likelihood that the person could be subject to the death penalty. This pragmatic and mutually respectful compromise reflects a level of trust amidst the peer-to-peer character of today’s UK-Japan relationship, which lowers legal risk to a level where it is clearly surpassed by the strategic benefits. 

Not everyone is happy with the RAA. China Daily reacted with the headline: ‘Tokyo-London military pact raises tensions’, including the hyperbolic suggestion that the RAA is seen as ‘a bilateral version of NATO’. No one else in the Indo-Pacific seems troubled, though. Beijing will continue to object, seemingly oblivious to the fact that its bullying behaviour is the main factor driving its adversaries together. Sunak’s comment piece in the Nikkei newspaper was entitled: ‘UK will stand by Japan as China leverages its state power’.


Placed in the context of other developments in the area of strategic cooperation (trade, digital, and combat air), the RAA confirms the macro trend of alignment across the Euro-Atlantic and Indo-Pacific regions, and the vitality of security entrepreneurship among countries at the sub-superpower level.

By facilitating the exchange of military personnel between Japan and the UK for various purposes, this agreement indicates the elevation of the relationship above the level of normal cooperation between friendly countries but still below that of a NATO-type mutual defence treaty. Yet, the RAA does offer an opportunity for the bilateral relationship to assume some of the qualities implied by a formal alliance.

Dr Philip Shetler-Jones is a James Cook Associate Fellow in Indo-Pacific Geopolitics at the Council on Geostrategy. He works in the field of Europe-Asia security cooperation, with a personal focus on United Kingdom-Japan defence and security relations.

Embedded image credit: Number 10 (CC BY 2.0 cropped)

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