The EU’s Defence Ambitions: A Direct Threat to NATO and British Security

The European Union’s accelerating drive towards greater integration in defence and foreign policy presents a profound challenge to the North Atlantic Treaty Organisation, the bedrock of collective Western defence. For the United Kingdom, which has staked its post-Brexit security firmly on NATO primacy, this development is not merely a matter of European politics; it is a strategic risk to national security. The EU’s expanding defence architecture – centred on initiatives such as Permanent Structured Cooperation (PESCO), the European Defence Fund, and the Strategic Compass – duplicates existing NATO structures, fragments scarce resources, and promotes a vision of “strategic autonomy” that could ultimately weaken transatlantic solidarity.

Since Brexit, the United Kingdom has consistently affirmed NATO as the cornerstone of its defence policy. Successive British governments have emphasised that European security is best guaranteed through the Alliance, with its proven command structures, integrated planning processes, and unequivocal Article 5 commitment. Yet the EU has pursued an increasingly ambitious and parallel defence agenda. This is not a benign complement to NATO, as Brussels often claims, but a competing project that risks diluting Allied cohesion at a time when threats from Russia, China, and elsewhere demand unity rather than division.

The EU’s defence architecture is now extensive and complex. Permanent Structured Cooperation, launched in December 2017, currently comprises more than 60 projects involving 26 member states (all except Malta). These range from military mobility and cyber rapid response teams to joint development of next-generation systems such as main battle tanks and naval vessels. PESCO is binding: participating states must increase defence budgets, prioritise collaborative projects, and regularly report progress. The Coordinated Annual Review on Defence (CARD) monitors national plans and identifies shortfalls, performing a role strikingly similar to NATO’s own Defence Planning Process. The European Defence Fund provides billions of euros for research and capability development exclusively among EU entities, while the off-budget European Peace Facility has channelled over €17 billion in military assistance, notably to Ukraine.

The 2022 Strategic Compass further sharpened these ambitions, setting a target for a 5,000-strong EU Rapid Deployment Capacity by 2025 and calling for more joint procurement and industrial consolidation. The appointment in 2024 of a dedicated Commissioner for Defence and Space, together with proposals for defence bonds and a single market for defence products, signals an intent to create a genuinely integrated European defence identity. The Military Planning and Conduct Capability (MPCC) in Brussels already serves as an operational headquarters for non-executive EU missions and could expand further.

Proponents argue that these measures strengthen Europe’s contribution to NATO. Yet the reality is more troubling. Duplication is inherent: NATO already possesses the Alliance’s Defence Planning Process, the NATO Response Force, enhanced Forward Presence battlegroups, and a comprehensive framework for capability targets. European nations struggling to meet the NATO 2% spending guideline – a pledge reaffirmed at successive summits – are now diverting political and financial capital into parallel EU mechanisms. The result is inefficiency and fragmentation at a moment when defence investment must be maximised.

More dangerous is the underlying ideology of “strategic autonomy.” This concept, repeatedly championed by President Macron and embedded in EU strategic documents, implies a Europe able to act independently of the United States when necessary. While understandable as a long-term aspiration, it risks eroding the transatlantic link that has deterred aggression for seventy-five years. If EU members increasingly prioritise Brussels-led initiatives over NATO commitments, Alliance decision-making could become paralysed in a crisis. Divergences in foreign policy – on issues from China to the Middle East – would be amplified by deeper defence integration, creating conflicting loyalties for member states that belong to both organisations.

For the United Kingdom, the implications are particularly acute. Excluded from core EU instruments such as the European Defence Fund and most PESCO governance, Britain is reduced to third-country status. Although invited to participate in select PESCO projects on a case-by-case basis, the overall trajectory marginalises a nation that remains Europe’s largest defence spender and one of NATO’s two nuclear powers. British industry risks losing ground to EU-protected competitors, while operational cooperation could become subordinated to Brussels’ political priorities. In any future European crisis, the United Kingdom might find its closest continental partners prioritising EU command structures over NATO ones.

History offers cautionary lessons. Attempts to create autonomous European defence structures – from the failed European Defence Community in the 1950s to the St Malo declaration – have repeatedly foundered on the reality that only NATO provides credible deterrence. The EU’s battlegroups, conceived in 2007, have never been deployed precisely because political will defaults to national or NATO frameworks in genuine crises. Today’s more ambitious agenda risks repeating this pattern on a grander scale, wasting resources while achieving little additional capability.

The United Kingdom must respond firmly. London should continue to insist, in every NATO forum, that European defence efforts must unequivocally complement rather than compete with the Alliance. Bilateral partnerships – notably the Lancaster House treaties with France and the deepening AUKUS framework – offer more effective routes to capability enhancement than absorption into EU structures. Above all, Britain should champion increased defence spending directed through NATO channels, reinforcing the Alliance as the indispensable guarantor of European security.

The EU’s defence expansion is not an abstract bureaucratic exercise; it is a strategic choice with real consequences. If allowed to undermine NATO’s primacy, it will weaken the very alliance upon which British security depends. Vigilance is required to ensure that European ambition strengthens, rather than fragments, the collective defence of the West.