Prime Minister Boris Johnson meets Japanese Prime Minister Fumio Kishida on Thursday to bolster defence and trade cooperation, part of Britain's post-Brexit policy to deepen ties with nations in the Indo-Pacific region.
With talks expected to focus on measures to put pressure on Russian President Vladimir Putin over his country's invasion of Ukraine, the two leaders will also agree in principle a defence agreement allowing British and Japanese forces to work together.
Johnson will announce the Reciprocal Access Agreement as a "landmark defence partnership", which will see British and Japanese Armed Forces deploy together to carry out training, joint exercises and disaster relief activities.
The two leaders will observe a Royal Air Force fly past and inspect a guard of honour.
"As two great island democracies ... the UK and Japan are focused on driving growth, creating highly skilled jobs and ensuring we remain technology superpowers," Johnson said in a statement before the visit.
"The visit of Prime Minister Kishida will accelerate our close defence relationship and build on our trade partnership to boost major infrastructure projects across the country - supporting our levelling up agenda."
Since Britain left the European Union in January 2020, Johnson has moved to expand his nation's influence among countries in the Indo-Pacific region, describing it as "increasingly the geopolitical centre of the world".
The visit will also look to strengthen trade ties, building on a deal struck in 2020 that marked Britain's first post-Brexit free trade agreement. Former business minister Greg Clark will be named as trade envoy to Japan.
Britain, seeking new export markets as part of a tilt away from its European neighbours, now has its sights set on joining a trans-Pacific trade pact of which Japan is a member and also responsible for overseeing the British application.