LONDON — Britain has signed a major defense agreement with Japan, giving the two nations the ability to deploy troops in the other country.

The British government said the agreement is the most significant defense pact signed between the two nations in over a century.

The move to strengthen defense ties comes as Japan rushes to significantly boost defense spending in response to growing Chinese military might in the Asian region.

What the British are calling a “landmark” agreement was signed by British Prime Minister Rishi Sunak and his counterpart Fumio Kishida during a visit to London by the Japanese leader.

Signing the deal, Sunak said: “We have written the next chapter of the relationship between the UK and Japan – accelerating, building and deepening our ties. We have so much in common: a shared outlook on the world, a shared understanding of the threats and challenges we face, and a shared ambition to use our place in the world for global good.”

The signing of the reciprocal access agreement comes just weeks after the UK and Japan teamed up, alongside Italy, to develop a next-generation combat jet through the new Global Combat Air Programme.

The aircraft represents the largest international defense collaboration project undertaken by Japan.

There are already collaborative efforts underway between the two sides on missile, jet engine and sensor capabilities.

Last month, the UK and Japan also launched a new UK-Japan digital partnership to strengthen cooperation across cyber resilience, online safety and semiconductors.

To date Britain is the only European nation to have an access agreement with Tokyo.

Australia signed a similar pact last November.

British policy in recent years has seen a shift towards greater involvement in the Asia-Pacific region.

That’s principally about trade, as among other things London is attempting to join the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), a free-trade bloc with a combined GDP of £9 trillion, or $11 trillion.

But defense ties have also been strengthened as part of the British tilt towards the Asia-Pacific region.

British warships and Typhoon combat jets have visited Japan in recent years, and the British Army participated in an exercise in 2018 and followed that up with the Vigilant Isles 22 exercise. That drill last year saw troops from the two nations participate in war games on island defense in Gunma prefecture in Central Japan.

Andrew Chuter is the United Kingdom correspondent for Defense News.

More In Europe