The treaty builds on a defence pact the UK and Germany, two of the biggest European supporters of Ukraine, signed last year committing to closer co-operation against the growing threat from Russia
Britain and Germany signed a wide-ranging friendship treaty on Thursday, deepening ties in areas ranging from defence to transport, to mark Friedrich Merz’s first trip to London as chancellor, the latest visit to help reset UK ties with the EU.
Merz’s day trip follows a three-day state visit to Britain by French President Emmanuel Macron, signalling greater cooperation between Europe’s top three powers at a time of threats to the continent and uncertainty about their US ally.
“This is a historic day for German-British relations,” Merz said at the signing ceremony in the Victoria and Albert museum, co-founded by Britain’s Queen Victoria and her husband Prince Albert, of German origin. “We want to deepen our cooperation in the field of defence, in foreign policy, but also in economic and domestic policy.”
Coming nearly a decade after Britain voted to leave the European Union, the treaty is, on the one hand, a sign of the normalisation of German-British relations, said Nicolai von Ondarza at Berlin’s SWP think-tank. “On the other hand, the treaty is a sign that the UK has become even more important as a security partner due to transatlantic uncertainty.”
Europe has been confronted with new US tariffs since President Donald Trump returned to the White House as well as questions about the US commitment to defend its European allies, including Ukraine against Russia’s invasion.
The treaty includes a clause on mutual assistance which, “in light of the Russian war of aggression against Ukraine, is highly significant”, a German official said earlier this week.
It builds on a defence deal agreed last year that included the joint development of long-range strike weapons, and comes after France and Britain agreed last week to reinforce cooperation over their respective nuclear arsenals.
As part of Thursday’s announcement, Britain and Germany pledged to “pursue joint export campaigns” to drum up orders from other countries for equipment they make jointly, such as the Typhoon Eurofighter jet and the Boxer armoured vehicle.
That could help boost sales and represents a significant reversal from the previous 10 years, when Germany blocked Saudi Arabia and Turkey from buying Typhoons. Typhoons are made by a consortium of European companies, including BAE Systems in Britain and Airbus in Germany, with the different partner governments responsible for orders to different countries; the Boxer is made by a German-British joint venture, Rheinmetall BAE Systems Land.
Further deepening ties, a German defence tech company, Stark, has also agreed to build a new factory in Britain, the first production facility outside of Germany, to create AI-powered unmanned systems.
Beyond defence, the treaty also includes an agreement to develop a new direct rail link between the two countries and to jointly combat irregular migration, part of Starmer’s push to reduce the number of asylum seekers arriving in Britain to try to fend off the populist Reform UK party. Germany pledged to outlaw the facilitation of illegal migration to Britain, with a law change by the end of the year.
That would give law enforcement the tools to investigate warehouses and storage facilities used by migrant smugglers to conceal dangerous small boats intended for illegal crossings to Britain. Merz and Starmer discussed ways to boost European support for Ukraine, following Trump’s announcement of a plan to bolster Kyiv’s stockpile by selling American weapons to NATO allies who would in turn send arms to Kyiv.
Merz signaled that those plans are still a work in progress, saying it might take “days, perhaps weeks” before weapons reach Ukraine. He said that “above all, we need clarity on how weapons systems that are given up from the European side will be replaced by the U.S.”
During the trip the leaders announced that German defense startup Stark, which makes drones for Ukraine, will open a factory in England. They also agreed to jointly produce defense exports such as Boxer armored vehicles and Typhoon jets, and to develop a deep precision strike missile in the next decade.
Starmer also praised Merz for his help curbing the smuggling gangs that brought 37,000 people across the English Channel from France in small boats in 2024, and more than 22,000 so far in 2025. Dozens have died attempting the journey. Berlin agreed last year to make facilitating the smuggling of migrants to the U.K. a criminal offence, a move that will give law enforcement more powers to investigate the supply and storage of small boats to be used for the crossings.
Merz committed to adopting the law change by the end of the year, a move Starmer said “is hugely welcome.”
