The United Kingdom and Japan have signed a landmark defence agreement, the Reciprocal Access Agreement, which will allow both nations to deploy troops on each other's soil for joint military exercises and operations. The deal, announced in Tokyo by Prime Minister Rishi Sunak and his Japanese counterpart Fumio Kishida, marks the most significant bilateral defence arrangement between a European power and an Asian nation since the Second World War.
The agreement coincides with a surge in bilateral trade, which reached £18bn in 2022, a record high. The economic relationship has been bolstered by the UK’s accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), a trade bloc that includes Japan. The UK formally signed the CPTPP accession treaty in March, which is expected to further increase trade flows.
Foreign Secretary James Cleverly described the pact as a “historic moment for the UK and Japan’s defence relationship”, adding that it would “help keep our people safe and our regions secure”. The agreement allows for streamlined customs procedures and joint training, and is part of a broader effort to counterbalance China’s growing assertiveness in the Indo-Pacific.
Japan’s Ministry of Defence noted that the reciprocal access arrangement was “necessary to further deepen cooperation between the Japan Self-Defense Forces and the British Armed Forces”. The deal has been in negotiation since 2021, following the UK’s departure from the European Union, which freed London to pursue independent trade and security deals.
The two countries have also committed to joint development of next-generation fighter jets, known as the Global Combat Air Programme, which will see BAE Systems and Mitsubishi Heavy Industries collaborate on advanced technology. The programme is expected to deliver a supersonic stealth fighter by 2035.
Analysts have noted that the UK-Japan relationship is increasingly shaped by shared concerns over regional stability. Professor Tim Huxley of the International Institute for Strategic Studies said: “The agreement reflects a convergence of strategic interests. Both countries view China’s military modernisation and activity in the South China Sea as a challenge to the rules-based international order.”
The UK has deepened ties with other Indo-Pacific nations in recent years, including Australia and the United States via the AUKUS security pact, which aims to provide Australia with nuclear-powered submarines. Japan has also been strengthening its own defence capabilities, announcing a doubling of its defence budget to 2 per cent of GDP by 2027.
Critics have questioned the cost of the UK’s pivot to the Indo-Pacific, particularly given ongoing budget pressures on the Ministry of Defence. The Royal Navy has faced reductions in surface vessel numbers, though the Government has committed to increasing defence spending to 2.5 per cent of GDP by 2030.
The deal will be subject to parliamentary approval in both countries, though it is expected to pass with strong cross-party support. The first joint exercises under the agreement are likely to take place later this year.
