Fractured deterrence? Franco-British nuclear doctrine convergence after Brexit and its implications for European security

Abstract

In the wake of Brexit and increased geopolitical uncertainty, calls for a European nuclear deterrent have resurfaced. This article compares the nuclear doctrines of France and the United Kingdom to assess whether they could form the basis of a joint European deterrence framework. Despite shared principles such as minimum deterrence and second-strike capability, the two powers differ sharply in institutional alignment, strategic culture and political intent. France positions its arsenal as a tool of strategic autonomy and potential European leadership, while the UK embeds its deterrent within NATO and remains dependent on the United States. These divergences, far from being just technical, are also political. The article argues that current doctrines do not allow for a credible shared deterrent architecture. Without supranational mechanisms for strategic decision-making and political commitment, European extended deterrence will remain structurally fragmented and dependent on U.S. guarantees.