In a landmark move toward greater European military autonomy, UK Prime Minister Keir Starmer and French President Emmanuel Macron are set to unveil a new defense pact that includes joint nuclear deterrence commitments and expanded cooperation on unauthorized migration. The agreement, to be announced Thursday at a British military base, marks the first time the two nuclear-armed nations have formally pledged to coordinate their arsenals in the event of a major threat to Europe.

A Unified Nuclear Signal to Moscow

The pact does not constitute a formal European nuclear shield, but a statement from the UK Ministry of Defense declared that “there is no extreme threat to Europe that would not prompt a response by both nations.” The move reflects growing pressure on Europe to develop its own security architecture amid declining U.S. engagement in Ukraine under President Donald Trump, who has repeatedly urged Europe to "defend itself."

Britain and France remain the only nuclear powers in Europe and are seeking to project unity as Ukraine continues to resist Russian aggression more than three years into the war.

Migration Crisis and Political Stakes

In parallel, Starmer and Macron are expected to present a new bilateral strategy to reduce unauthorized crossings of the English Channel. Britain has seen a sharp rise in small boat arrivals since losing access to EU migration frameworks post-Brexit, creating political headaches for Starmer’s Labour government.

Nigel Farage, leader of the right-wing Reform UK party, used the occasion to demand an end to undocumented male migration, accusing Macron of “arrogance.” Starmer rebuffed the attack, accusing Farage of sabotaging cooperation while offering no viable solutions. “He wants to milk it and exploit it,” Starmer said.

Post-Brexit Reconciliation

The summit marks a diplomatic thaw following years of tension after Brexit, which severed many formal ties between the UK and EU institutions. Macron, addressing Parliament earlier in the week, called for renewed bilateral cooperation to defend international order and support multilateralism.

Starmer and Macron, who first met for defense talks before Trump’s return to office in January, are also expected to rally support among a “coalition of the willing” for continued Ukraine defense, despite hesitation from other European countries to send military assets like fighter jets.

Toward a European Security Pillar

Analysts view the nuclear agreement as a modest but symbolic step toward a more autonomous European defense posture. With NATO still in place but U.S. priorities shifting, the UK–France pact may form the basis for a future multilateral security structure within Europe, particularly as leaders brace for prolonged instability on the continent’s eastern flank.

The leaders plan to hold a virtual summit with coalition members on Thursday to reinvigorate support for Ukraine and demonstrate that Europe's nuclear powers remain committed to confronting common threats—together.