When the British and Japanese Prime Ministers meet in London on Wednesday, they will sign a "hugely significant" new defense agreement allowing UK troops to deploy in Japan, as per Downing Street.

The pact is the latest manifestation of London's rising interest in the Asia-Pacific area, as well as Tokyo's efforts to fortify its alliances with the West.

The agreement establishes a legal framework for the deployment of British and Japanese troops on each other's land for training and other purposes.

Prime Minister Rishi Sunak's office described it as "the most significant defense agreement between the two countries in more than a century."

"In the past 12 months, we have written the next chapter of the relationship between the UK and Japan -- accelerating, building, and deepening our ties," said Sunak.

"This Reciprocal Access Agreement is hugely significant for both our nations -- it cements our commitment to the Indo-Pacific and underlines our joint efforts to bolster economic security," he added.

The negotiations for the treaty, which will be signed at the ancient Tower of London, began in 2021.

Japan inked a similar agreement with Australia in January, and Tokyo has lately revamped its defense and security policies fueling the already rising tensions in the Asia-Pacific region.

On his account, Euan Graham, a senior fellow at the International Institute for Strategic Studies, said the deal is "quite a significant step up for both countries in terms of their bilateral defense relationship."

British ships and aircraft can visit Japan, although it is "diplomatically complex" and necessitates foreign ministry approval each time.

The new agreement will create a "standing framework" instead, according to Graham.

This will allow one side to "send a destroyer to visit your coast guard, or an army group, or some Royal Marines who wish to train with the Japanese amphibious forces," Graham said, as quoted by AFP.

The big picture

Japan's postwar constitution is pacifist, limiting its military capability to presumably defensive operations.

However, the government authorized plans last month to increase defense expenditure to 2% of GDP by 2027, up from the typical 1% level, claiming that China poses the "biggest strategic danger ever" to its security.

The UK, Italy, and Japan said last month they will jointly develop a future fighter jet.

The proposed "Global Combat Air Programme" is expected to deliver its first jets by 2035, combining the three countries' expensive existing research into new aerial warfare technology, ranging from stealth capability to high-tech sensors.

A British patrol ship also last year took part for the first time in "Exercise Keen Sword," the regular Pacific training operation carried out by the Japanese and US navies.

It is worth noting that Japanese Prime Minister Fumio Kishida kicked off his seven-day tour of European countries, Canada, and the United States in the early hours of Monday.

This year, Japan holds the G7 presidency, and Kishida has pledged that the group will continue to support Ukraine, which is expected to be covered in his talks with Sunak.

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