A Partnership Built on Security: Post-Brexit Rapprochement between Germany and the United Kingdom
Since the UK’s withdrawal from the EU, UK-German relations have undergone a remarkable transformation: from Berlin’s deliberate distancing from London during the Brexit negotiations, when Germany consistently prioritised EU-27 unity over bilateral arrangements, to a gradual rapprochement, culminating, for the time being, in the 2025 Kensington Treaty of Friendship.
In the context of Germany’s Zeitenwende, defence policy has become a central pillar of bilateral relations, encompassing mutual defence commitments and nuclear dialogue. However, the diverging trajectories of defence spending raise questions about how these ambitions can be translated into practice.
Particular attention is paid to the comparison within the E3 triangle. Unlike the Lancaster House Treaties between the UK and France, the Kensington Treaty includes a bilateral mutual defence guarantee. For Berlin, the E3 format and “Weimar Plus” remain the preferred mechanisms for engaging the UK strategically, while the European Political Community, championed by Paris, and the “Coalition of the Willing” play no role in Franco-German-British cooperation.
Dr Nicolai von Ondarza is Head of the EU/Europe Research Division at the German Institute for International and Security Affairs (SWP) in Berlin and an Associate Fellow at Chatham House. His research focuses on Germany’s role in Europe, EU politics and institutions, EU–UK relations as well as democracy in Europe.
- This publication is available in:
French (pdf): Une association fondée sur la sécurité. Le rapprochement post-Brexit entre l’Allemagne et le Royaume-Uni
German (pdf): Mit Sicherheit eingebunden – Die bilaterale Wiederannäherung von Deutschland und Großbritannien nach dem Brexit
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DOI
Notes du Cerfa, No. 192, Ifri, October 2026
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The Study Committee on Franco-German Relations (Cerfa)
The Study Committee on Franco-German Relations (Cerfa) was created in 1954 by an inter-governmental agreement between the Federal Republic of Germany and France, in order to raise awareness of Germany in France and analyze Franco-German relations, including in their European and international dimensions. In its conferences and seminars, which bring together experts, political leaders, senior decision-makers and representatives of civil society from both countries, Cerfa develops the Franco-German debate and stimulates political proposals. It regularly publishes studies through two collections: Cerfa notes and studies as well as Franco-German visions.
Cerfa maintains close relations with the network of German foundations and think tanks. In addition to its research and debate activities, Cerfa promotes the emergence of a new Franco-German generation through original cooperation programs. This is how in 2021-2022, Cerfa led a program on multilateralism with the Konrad Adenauer Foundation in Paris. This program is aimed at young professionals from both countries interested in the issues of multilateralism in the context of their activities. It covered a wide range of themes relating to multilateralism, such as international trade, health, human rights and migration, non-proliferation and disarmament. Previously, Cerfa had participated in the Franco-German future dialogue, co-led with the DGAP from 2007 to 2020, and supported by the Robert Bosch Foundation and the Daniel Vernet group (formerly the Franco-German Reflection Group) which was founded in 2014 upon the initiative of the Genshagen Foundation.
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