(L-R) Britain's Defence Secretary Gavin Williamson, Japan's Defence Minister Itsunori Onodera, Japan's Foreign Minister Taro Kono and Britain's Foreign Secretary Boris Johnson examine a selection of historical naval artifacts in the Queen's House gallery on December 14, 2017 in London. Photo: AFP / Leon Neal

Japan and the UK have agreed to closer military cooperation, including joint development of a new air-to-air missile, in what the Asahi Shimbun describes as a new “semi-alliance” between the two nations.

Foreign Minister Taro Kono and Defense Minister Itsunori Onodera reportedly met with Boris Johnson, the British foreign secretary, and Gavin Williamson, the defense secretary, in London on December 14 and agreed to move ahead on joint research to develop missiles for fighter jets and other cooperation.

Asahi says the new coordination with Britain represents Japan’s first joint research on missiles that doesn’t involve the US. The big Japanese newspaper says the quickening defense relationship between Japan and the UK reflects “uncertainties over the US security commitment in East Asia and continuing concerns about China’s maritime advances.”

The semi-alliance between the two island nations also comes as Britain rethinks its diplomatic and defense policies in the face of a scheduled departure from the EU in March 2019.

In other military cooperation, Tokyo and London also agreed to hold the first-ever joint training exercises between Japan’s Maritime Self-Defense Force and the Royal Navy. The naval exercises are expected to occur when British frigates are deployed to the Asia-Pacific theater. British troops and soldiers from Japan’s Ground Self-Defense Force are also expected to hold joint drills in 2018.