British Prime Minister Keir Starmer (R) shakes hands with Japanese Prime Minister Sanae Takaichi ahead of talks at 10 Downing Street in London, Britain, 14 June 2026. Photo by ANDY RAIN / EPA

June 15 (Asia Today) -- Japanese Prime Minister Sanae Takaichi and British Prime Minister Keir Starmer issued a joint economic security declaration Sunday, pledging closer cooperation to stabilize and diversify supply chains amid growing concerns over China's restrictions on exports of rare earths and other critical minerals.

The agreements reflect a broader shift in Japan-Britain relations toward a close strategic partnership encompassing security, economic policy and advanced technology.

Takaichi and Starmer held talks and a working lunch lasting about two hours and 40 minutes at the British prime minister's residence in London, according to Japan's Foreign Ministry.

The leaders issued the Japan-UK Joint Declaration on Economic Security Cooperation and announced the UK-Japan Frontier Technology Partnership. They also held a smaller meeting for about 25 minutes and attended a business roundtable with executives from both countries.