Brexit regrets meet defense uncertainty: what happens to EU–UK security and Ukraine support now?

Former Irish Prime Minister Leo Varadkar said he still hopes the UK can “find a way to be back at the EU table,” marking a decade since the 2016 Brexit referendum. Speaking to Euronews, Varadkar called Brexit a “wrong decision” driven by “increased populism and nationalism,” and he reiterated his regret for the outcome. The comments arrive as European leaders revisit the practical costs of separation for trade, regulation, and—critically—security cooperation. In parallel, German outlet DW framed the political question around the UK’s leadership change: British Prime Minister Keir Starmer has announced his resignation, raising uncertainty about continuity in EU–UK defense coordination. Strategically, the cluster points to a convergence of two fault lines: post-Brexit institutional distance and the urgent need for integrated European defense planning. Starmer was widely associated with support for Ukraine and with efforts to build a new EU–UK defense partnership, so his departure creates a policy transition risk at the exact moment Europe is trying to scale procurement and interoperability. The Le Figaro report adds a structural layer by highlighting European defense industrial dependencies, implying that political alignment alone will not solve capability gaps. The likely winners are actors that can capitalize on fragmentation—those able to supply components, set standards, or influence procurement—while the losers are European programs that depend on cross-border industrial ecosystems that remain incomplete. Market and economic implications center on defense procurement, industrial supply chains, and the broader risk premium for European security spending. If EU–UK defense talks slow or lose momentum, defense primes and subsystem suppliers tied to cross-border contracts could face delays, pushing investors toward firms with more diversified sourcing and backlog visibility. The “dependency” narrative also tends to lift demand for domestic production, which can affect industrial inputs such as aerospace materials, electronics, and specialized manufacturing capacity, even if specific commodities are not named in the articles. Currency and rates effects are indirect but plausible: uncertainty around defense policy continuity can widen the spread between European defense-related equities and global peers, especially for companies exposed to EU procurement cycles. What to watch next is whether the UK’s successor government signals continuity on Ukraine support and whether it preserves the momentum of an EU–UK defense partnership. In the near term, monitor statements from EU institutions and UK officials on defense cooperation frameworks, plus any references to interoperability, joint procurement, or industrial collaboration. For the industrial dependency issue raised by Le Figaro, the key trigger is whether EU and member-state procurement plans shift toward “sovereign” sourcing or new industrial compacts that reduce reliance on external suppliers. Escalation would look like abrupt policy reversals on Ukraine or a collapse in defense partnership talks, while de-escalation would be continuity messaging and concrete working-group deliverables within weeks of the leadership transition.

Geopolitical Implications

• 01

  A UK leadership transition could disrupt EU–UK defense coordination and affect interoperability and procurement timelines.

• 02

  Brexit’s institutional legacy remains a friction point for security governance, not just trade policy.

• 03

  Defense industrial dependencies may limit rapid capability scaling and increase external leverage.

• 04

  Ukraine support continuity is becoming a key test of European alliance cohesion.

Key Signals

• —Successor UK leadership messaging on Ukraine support and EU–UK defense continuity.
• —EU institutional statements on defense partnership frameworks and interoperability.
• —Procurement plan shifts toward sovereign sourcing or new industrial compacts.
• —Evidence of working-group deliverables within weeks of the leadership change.