In a landmark move to bolster European defense, France and the United Kingdom announced on Thursday a new phase of cooperation centered on their nuclear arsenals. The initiative,

formalized during French President Emmanuel Macron’s state visit to Britain, aims to strengthen deterrence capabilities amid growing instability and uncertainty over U.S. commitments to NATO.

“This morning, we signed the Northward Declaration, confirming for the first time that we are coordinating our independent nuclear deterrence,” said UK Prime Minister Keir Starmer at a joint press conference with Macron. “From today, our adversaries will understand that any extreme threat to this continent would trigger a unified response from our two nations. This is a powerful signal of our partnership.”

The announcement marks a historic moment in Franco-British defense ties, especially as Europe grapples with questions about the reliability of U.S. support. Former U.S. President Donald Trump's skepticism toward NATO and conciliatory stance on Russia had already sown doubts about the transatlantic alliance's long-term durability.

During their visit to Northwood Headquarters, Starmer and Macron also convened a meeting of the “Coalition of the Willing,” reaffirming their joint commitment to European security. Though the new nuclear coordination is separate from efforts to support Ukraine, it reflects a broader strategy to enhance Europe’s self-reliance in defense matters.

President Macron confirmed that an oversight committee will be established to manage and synchronize the two nations’ cooperation on nuclear deterrence. “We’re not merging our deterrents, but we’re no longer excluding coordination. That’s a critical message—both to our allies and to our adversaries,” Macron said.

While both countries will retain independent control over their nuclear arsenals and maintain strategic ambiguity, the collaboration marks a significant shift in Europe's nuclear posture. It comes as Macron pushes forward with his proposal for a broader European strategic dialogue on nuclear defense, potentially extending France's deterrent umbrella to other EU nations.

Currently, the U.S. provides the bulk of Europe’s nuclear defense and has tens of thousands of troops stationed across the continent. In contrast, France maintains a nuclear stockpile of 290 warheads—submarine- and air-launched—at a cost of approximately €5.6 billion ($6.04 billion) annually. The UK’s nuclear program, while operationally independent, relies heavily on American missile technology and support for acquisition and maintenance.

The Northward Declaration signals a deepening of Franco-British ties and a united front in safeguarding Europe at a time of shifting global alliances. Photo by Wikimedia commons.