German-British relations are warmer than they’ve been in a long time. The Kensington Treaty, or, as many prefer to call it, the German-British Friendship Treaty, is a first-of-its-kind: legally binding and comprehensive, covering economic links, security and defense, and people-to-people relations.
After what has been a difficult decade, the treaty signals a new chapter in bilateral relations. It holds out the potential for deeper cooperation. As always, however, the proof of the pudding will be in the eating. Not least, limited bandwidth and other pressing priorities both in the United Kingdom and Germany might impinge on implementation and the ability of the two sides to grasp the undoubted potential gains to be had.
What is in no doubt is that we have come a long way. In 2021, just after the signing of the EU-UK Trade and Cooperation Agreement (TCA), trust was at an all-time low. The 2021 German party manifestos revealed nothing so much as concern about the UK: fears of a possible race to the bottom on environmental and labor standards, and warnings that legal obligations and the Good Friday Agreement must be respected.
And the impact of Brexit went beyond perceptions. By 2022, the UK had fallen out of the top 10 list of Germany’s major trading partners, having ranked third in 2016. Out of sight, out of mind it also fell off German mental maps. Polling for the Koerber Stiftung in September 2024 showed that fewer than 1 percent of German citizens saw the UK as Germany’s most important foreign policy partner (with 47 percent naming the United States, 27 percent France, and 3 percent, remarkably, Russia).
Fast forward to 2025, and this situation has changed beyond recognition, partly as a result of the change of government in the UK, partly due to the increasingly fraught European security environment.
Defining Berlin as a Partner
The Labour leadership was quick, even in opposition, to define Germany as a key partner. Both hailing from the same political family, then Chancellor Olaf Scholz and (the equally dull) Keir Starmer made for a good team. Preparations for the Trinity House Treaty on defense started with Labour still in opposition, driven by a close relationship between then Shadow Secretary for Defense John Healey and Germany’s defense minister, Boris Pistorius.
The Starmer-Scholz entente undoubtedly helped to get the ball rolling, but the rapprochement went beyond party lines. With the war in Ukraine and the re-election of the mercurial Donald Trump as US president, most of Germany’s political parties—from the center-left Social Democrats (SPD) to the center-right Christian Democrats (CDU/CSU) to the pro-business Free Democrats (FDP)—made a strong case for closer security and defense ties with the UK in their 2025 manifestos. Consequently, negotiations on the friendship treaty were seamlessly picked up by the new CDU-led government, keen to take on a leadership role in Europe, and insistent that the UK is an important partner.
A Wide-Ranging Agenda
Perhaps the most striking thing about the Friendship Treaty, signed on July 17, is its breadth. It covers areas ranging from diplomacy to security to development; defense cooperation; internal security, justice and migration; economic growth, resilience and competitiveness; open and resilient societies; and climate, energy, nature, environment, and agriculture.
Clearly it remains an open question as to whether the two sides can really deliver on such a wide-ranging agenda. Equally, there is a case to be made that on some issues (growth, resilience, and competitiveness most obviously) effectiveness will hinge as much on UK-EU relations as on any deals signed with individual member states.
Security and defense lie at the heart of the new arrangements, with London and Berlin committing to joint precision‑strike projects and even a bilateral mutual‑defense clause linked to NATO. Again, much will hinge not only on whether the two countries deliver on their ambitious plans to increase defense spending, but also on how effectively European states manage to work together multilaterally to combat a more threatening security environment.
Closing the Triangle
The treaty can also be seen as the missing piece in the triangle that is German, British, and French relations based on the Kensington, Lancaster House, and Élysée/Aachen accords. Certainly, these documents provide a strong basis for trilateral cooperation, but the ultimate effectiveness of the E3 will depend not only on treaties but also on how far Paris and Berlin are willing to risk pushback from other EU member states in coordinating closely outside the EU framework with the UK.
The treaty also consolidates previous attempts at formalizing the relationship. It introduces a German-British summit (or as the treaty describes it, “government ministerial consultations led by Heads of Government”) every other year. This is in addition to the Strategic Dialogue between Foreign Ministers set up in 2021, the Trinity House Defense Ministerial Council, and the UK-Germany Home Affairs Dialogue, both proposed in 2024.
Taken together, this amounts to a fair bit of bilateral coordination, which will go some way toward replacing the regular contacts maintained by UK and German ministers within EU institutions. That being said, there is a big difference between occasional summits and the day-to-day interactions that characterize links between member states. And there is, at present, no forum for parliamentarians similar to the model of the Franco-German parliamentary assembly.
Finally, the treaty is supposed to deliver direct benefits for citizens. German Chancellor Friedrich Merz and Keir Starmer, both under intense political pressure at home, must show that politics can deliver should they wish to remain in power beyond the next elections. The onus is therefore on “delivering tangible benefits” via 17 priority projects, including pledges on visa-free travel for school trips and direct train links between Germany and the UK, which, if delivered, could make a real difference.
No Guarantees
The ultimate import of all this will depend on a number of factors, not least the evolution of the UK-EU relationship. While the UK government has been quick off the mark in reaching new bilateral agreements, the same cannot be said for its relations with the EU. At their May summit, the two sides agreed a list of future areas for cooperation, with formal negotiations set to start later this year. There is a clear overlap in priorities between the UK-EU agenda and those characterizing relations with member states. Recurring topics range from Ukraine and irregular migration to e-gates at airports. Yet while closer bilateral cooperation in these areas matters, the real impact will likely come from cooperation at the European level (where also some of the competencies lie).
And there is no guarantee that EU-UK negotiations will proceed smoothly. There is always the danger that frustration with slow progress in these talks might bleed into bilateral relations with member states. Not least, the UK's new sense of urgency about securing quick agreements does not seem, to date at least, to be mirrored on the EU side. As the introduction of the treaty reminds us, bilateral UK-German links will be built in the context of “the Federal Republic of Germany’s membership in the European Union and the commitments and obligations resulting therefrom.”
As important as the new bilateralism is, then, it is closely and crucially linked to broader relations between the UK and the EU as a whole.
Jannike Wachowiak is a research associate at “UK in a Changing Europe,” specializing in EU-UK relations.
Anand Menon is the director of “UK in a Changing Europe” and Professor of European Politics and Foreign Affairs at King’s College London.
