Britain and Japan signed an £18 billion ($24.1 billion) investment package on 15 June 2026, as Japanese Prime Minister Sanae Takaichi visited Downing Street ahead of the G7 summit in France. Prime Minister Keir Starmer said the agreements would build a 'new era of co-operation' between the two countries. The deal spans offshore wind, infrastructure, financial services, defence and life sciences, and encompasses more than ten commercial and government agreements.
Downing Street said Japanese firms will commit up to £9 billion to UK offshore wind and more than £9 billion to UK infrastructure and financial services, with the latter forming a five-year pipeline expected to build new towns and provide high-quality office space and innovation hubs. Rolls-Royce (RR.L) is deepening its collaboration with Japan's Atomic Energy Agency through a new agreement to develop next-generation technologies. Japanese life sciences firm Eisai (4523.T) is set to invest £48 million focused on artificial intelligence and quantum technology.
The two leaders also reaffirmed their commitment to the Global Combat Air Programme, the trilateral fighter jet initiative launched in 2022 by Britain, Italy and Japan that aims to deliver a next-generation warplane by 2035 to replace the Eurofighter Typhoon. Discussions will additionally include helping UK defence firms access Japanese investment, according to Downing Street. The BBC noted it is not clear how much of the £18 billion represents genuinely new money versus previously announced plans [Source: BBC Business].
The announcement follows the recent resignation of Defence Secretary John Healey over a dispute about long-term military funding, with Armed Forces Minister Al Carns and two parliamentary aides also having exited. The deal also arrives as the UK's economy struggles to grow, according to BBC Business, which reported that experts have warned the conflict involving the US, Israel and Iran could hit Britain particularly hard [Source: BBC Business].
The deal adds to a growing record of Japanese capital commitments to the United Kingdom. According to the British Chamber of Commerce in Japan, Japan is the UK's fifth largest investor, with £92 billion invested in the country as of 2023. Total trade between the two countries is currently worth around £140 billion, according to the UK government [Source: AFP]. In July 2025, the UK government signed a separate £7.5 billion clean energy investment memorandum with Sumitomo Corporation covering offshore wind and hydrogen over ten years. That followed a May 2023 round in which Japanese firms committed almost £17.7 billion across offshore wind, green hydrogen and real estate.
Sources: The Guardian, Bloomberg, BBC Business, City AM, AFP, GOV.UK, British Chamber of Commerce in Japan