LONDON, 10 July 2025 — British Prime Minister Keir Starmer and French President Emmanuel Macron are set to unveil a groundbreaking Anglo-French nuclear defense declaration, marking the most significant military coordination between the two nuclear powers since the end of the Cold War. The historic agreement, anticipated to be signed during Macron’s three-day state visit to the United Kingdom, signals a major step forward in European defense integration amid escalating global tensions and evolving security paradigms.
The declaration, details of which were confirmed by officials from both Downing Street and the Élysée Palace on Wednesday, affirms that while the United Kingdom and France will unequivocally maintain independent nuclear arsenals, they are prepared to coordinate their deterrents in the event of an “extreme threat to Europe.” The joint commitment underscores the unambiguous resolve of both nations to act decisively against existential risks to European security.
“The respective deterrents of both countries remain independent but can be co-ordinated,” the joint statement is expected to read, adding that “there is no extreme threat to Europe that would not prompt a response by both nations.” This phrasing echoes long-standing strategic dialogues between London and Paris, often emphasizing their unique roles as Europe’s sole nuclear-armed powers within NATO.
A Landmark Moment for European Defense Cooperation
The agreement culminates Macron’s state visit to the UK, which includes a high-level Anglo-French summit in London. Prime Minister Starmer, in his first major foreign policy initiative since his July election, is expected to frame the accord as a fresh chapter in the longstanding defense alliance between the two nations, which has roots in the 2010 Lancaster House Treaties. These treaties established a framework for extensive bilateral defense cooperation, including joint expeditionary forces and reciprocal access to training facilities, as detailed by the UK Ministry of Defence.
The bilateral summit will also serve to significantly “reboot” defense ties after a period of post-Brexit uncertainty and diplomatic rifts, particularly over the AUKUS security pact. A key outcome will be deepened collaboration on joint weapons systems, specifically the Storm Shadow cruise missile (known as SCALP in France). This missile, a product of previous Anglo-French joint development through MBDA, has proven pivotal in supporting Ukraine’s defense against Russian aggression.
According to defense officials, both countries will now commit to jointly acquiring additional Storm Shadow/SCALP missiles and accelerating work on a next-generation successor system. This initiative is part of a broader “Entente Industrielle” designed to make defense innovation a key growth engine across the Channel and foster greater defense industrial autonomy. For broader context on the strategic implications of joint defense initiatives and how they intersect with the EU Economy, The Politico has reported extensively on Europe’s burgeoning defense spending and its economic impact.
Strategic Unity in a Volatile World
This deepening of defense ties comes as NATO refocuses its long-term strategy amid mounting geopolitical uncertainty. European powers have grown increasingly concerned about the reliability of U.S. extended deterrence, especially in light of shifting political dynamics in Washington and debates over burden-sharing within the alliance. The Anglo-French agreement could be viewed, in part, as a direct response to this uncertainty—an effort to build robust intra-European deterrence that can stand alone if necessary. This aligns with a growing consensus that Europe must strengthen its nuclear deterrence amid U.S. uncertainty.
The initiative is also expected to strengthen NATO’s overall nuclear posture. France and the UK are both long-standing contributors to the alliance’s deterrent framework, and increased coordination between them could streamline response planning and reinforce credibility in the face of threats from Russia and other adversaries. NATO’s strategic concept, refined at the Vilnius (2023) and Washington (2024) summits, emphasizes robust deterrence and defense, making such bilateral agreements highly relevant.
The move follows a broader trend among EU states to rearm and rethink security architecture, as covered in our recent pieces on Germany’s significant defense shift and Nordic cooperation within our European Defense category. This collective drive for enhanced security capabilities is also exemplified by decisions like Poland’s €662 million investment in 155mm ammunition production and the UK’s efforts to build more shell factories to support European defense.
Broader Security Agenda: Ukraine and Migration
Alongside the nuclear declaration, Macron and Starmer will participate in a virtual summit of the “coalition of the willing” on Ukraine—an informal group of allied countries committed to ongoing military and financial support for Kyiv. Both leaders are expected to reaffirm their long-term commitment to Ukraine’s sovereignty and continued arms deliveries, including systems developed through their joint industrial base, vital for Kyiv’s defense in the face of ongoing aggression. This reflects the deep commitment to addressing global conflicts.
The summit will also address the politically sensitive issue of cross-Channel migration. The leaders will focus on reinforcing joint enforcement mechanisms aimed at curbing irregular flows of migrants. While this aspect of the agenda may appear distinct from defense, officials have emphasized the importance of coordinated maritime patrols and intelligence-sharing between the UK and France to manage this shared challenge effectively. As The Politico has noted in its EU Politics coverage, migration remains a key electoral pressure point across Europe, significantly influencing both domestic and foreign policy calculations, affecting areas from societal challenges to economic policies.
Renewing Trust Post-Brexit and Shaping Future EU Defense
Macron’s state visit and the London summit are being widely cast as a symbolic and practical reset for Anglo-French relations. While the bilateral military relationship demonstrated resilience through the turbulence of Brexit and the diplomatic fallout over AUKUS, today’s declaration solidifies a return to strategic trust and operational alignment at the highest levels.
“Today’s agreements take our partnership to the next level,” Prime Minister Starmer is expected to say, describing the Anglo-French alliance as “a pillar of European security.” French officials similarly referred to the initiative as a “foundational moment” for joint strategic autonomy within Europe. This also aligns with France’s continuous commitment to increasing its military budget to meet NATO obligations, as outlined in its 2025 military budget.
The declaration also comes at a time when the EU is actively exploring more cohesive defense mechanisms, including renewed debate over the idea of a European nuclear umbrella. While France has previously floated this concept, particularly within the PESCO (Permanent Structured Cooperation) framework, this robust bilateral approach could serve as a model for future agreements across the continent, offering a blueprint for enhanced intra-European defense collaboration, complementing broader EU initiatives like joint ammunition procurement.
Outlook: Sustained Momentum for European Strategic Autonomy
The Anglo-French nuclear coordination is expected to remain largely declaratory for now, without formal operational integration of their independent arsenals. However, it opens the door to significantly enhanced intelligence sharing, joint exercises, and harmonized command protocols under crisis conditions. Further institutional collaboration through NATO and the EU’s evolving defense architecture is also highly likely.
With global threats rising—from an assertive Russia to increasing instability in the Indo-Pacific—the initiative reasserts Europe’s capability and will to act decisively in its own defense. As The Politico continues to report, such moves are fundamentally redefining the European security order for what is increasingly perceived as a post-American era, where Europe must take greater responsibility for its own security.