Japan has expressed growing concern over China’s rapid military build-up, prompting the United Kingdom to deepen its strategic engagement in the Indo-Pacific. The development comes as British and Japanese officials finalise a new trade and defence agreement, underscoring London’s pivot towards the region post-Brexit.
The Japanese government’s annual defence white paper, released this week, described China’s military expansion as “the greatest strategic challenge” to regional stability. It noted a sharp increase in Chinese naval and air activity near Japanese territorial waters, including the Senkaku/Diaoyu Islands, which are disputed between Tokyo and Beijing. The paper also highlighted China’s growing nuclear arsenal, which is projected to double within the next decade.
In response, Britain has accelerated talks on a reciprocal access agreement with Japan, allowing joint military exercises and logistical support. The pact, expected to be signed later this year, would be the first of its kind for the UK in East Asia. British defence officials have emphasised that the arrangement is not directed at any specific country but is intended to bolster deterrence and uphold the rules-based international order.
Concurrently, the UK and Japan are finalising a comprehensive economic partnership. The agreement, building on the existing free trade deal signed in 2020, will cover digital trade, green technology, and supply chain resilience. Japanese automotive and electronics manufacturers have been pressing for greater access to British markets, while the UK sees Japan as a gateway to the wider Indo-Pacific region, which accounts for over 40 per cent of global GDP.
The UK’s Integrated Review of Security, Defence, Development and Foreign Policy, published in 2021, identified the Indo-Pacific as a priority zone. The tilt has been embodied by the deployment of the HMS Queen Elizabeth carrier strike group to the region in 2021 and the establishment of a British defence attaché office in Tokyo. Last year, the UK also signed the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, a trade bloc that includes Japan, Australia, and Canada.
China has criticised the growing security cooperation, accusing external powers of stoking regional tensions. A Chinese foreign ministry spokesperson this week said that “certain countries are using the Indo-Pacific concept to form exclusive blocs that undermine regional peace and stability.” Beijing has urged Japan to “respect China’s core interests and major concerns.”
Analysts view the UK-Japan alignment as a natural evolution of their shared interests. Both nations are island states and maritime powers with a stake in the freedom of navigation. They also share concerns about unstable supply chains, particularly in critical minerals and semiconductors. The new agreements are expected to provide a framework for joint research and investment in these sectors.
For Japan, the deepening ties with the UK offer a hedge against an increasingly assertive China and a less predictable United States under possible future administrations. For Britain, the partnership reinforces its post-Brexit identity as a global trading nation with enduring strategic reach. The speed with which both governments are moving suggests a recognised urgency. As the Japanese white paper warns, time for peaceful resolution may be limited.
