Professor Amelia Hadfield and Tea Zyberaj
Professor Amelia Hadfield is the Founder and Director of the Centre for Britain and Europe, based at the Department of Politics and International. Having graduated with a degree in Politics from the University of Surrey in 2022, Tea is a former Schuman Trainee at the European Parliament and also holds an MSc in European Politics and Policy from UCL. Her work focuses on EU governance, enlargement, and EU–UK relations.
Two Steps Forward, One Step Back?
When European Commission President Ursula von der Leyen and UK Prime Minister Keir Starmer signed the EU-UK Security and Defence Partnership (SDP) in May 2025, it was widely interpreted as a turning point after years of strained post-Brexit relations. The agreement reflected a shared reassessment of strategic priorities amid a rapidly deteriorating geopolitical environment.
Donald Trump’s renewed trade confrontations, uncertainty over long-term US commitment to European security, and Russia’s continued aggression against Ukraine created strong incentives for closer cooperation between London and Brussels. Against this backdrop, security and defence moved to the centre of renewed engagement, and the SDP signalled a shift beyond ad hoc bilateralism towards more structured cooperation.
It was in this context that the EU’s new Security Action for Europe (SAFE) instrument came to be seen as one of the first concrete tests of the partnership. By opening, at least politically, the door to UK participation in EU defence initiatives, SAFE appeared to offer a practical avenue for translating the reset into policy cooperation. Just months after the SDP was signed, however, the collapse of negotiations over UK participation in SAFE offered an early indication of the limits of this rapprochement.
While ambitious in tone, the reset remains largely declaratory. Translating political commitments into operational arrangements requires complex and politically sensitive compromises. SAFE’s failure revealed the structural constraints that continue to shape EU-UK engagement, particularly where defence, industrial policy, and EU governance intersect.
Why Brussels supported a reset
From a Brussels perspective, the reset was driven less by reconciliation than by strategic necessity. The EU has faced prolonged volatility since Brexit, and restoring a degree of predictability in relations with the UK was increasingly seen as essential. The UK remains a major European military actor, a nuclear power, a permanent member of the UN Security Council, and a leading contributor within NATO. In this context, closer coordination with London was viewed as a way to amplify European capabilities.
The broader geopolitical environment reinforced this logic. Throughout 2025, the EU struggled with what many referred to as a pattern of paralysis and reactiveness in the face of mounting external pressures. Von der Leyen’s call for “Europe’s independence moment” captured a growing consensus that the Union needed to move beyond rhetorical commitments and develop credible instruments to secure its own defence.
Within this framework, cooperation with closely aligned partners became important to the EU’s capacity-strengthening efforts. For several member states, including Italy and Germany, this logic extended in particular to the UK, given its defence capabilities and longstanding role in European security. As a result, they supported more inclusive approaches to defence-industrial initiatives, recognising both the practical benefits of UK involvement and the limits of purely intra-EU solutions.
At the same time, support for renewed engagement was constrained by internal trade-offs within the EU. The urgency to accelerate defence cooperation in a deteriorating security environment had to be balanced against enduring concerns over maintaining control, safeguarding European defence-industrial interests, and preserving the integrity of EU governance frameworks. These tensions became increasingly salient as political aspirations for cooperation confronted the practical design and implementation of EU defence instruments. It was against this backdrop that the reset began to be tested, not at the level of political intent, but through the design of concrete EU defence instruments, most notably the Security Action for Europe (SAFE).
SAFE as the first major stress test
Launched in March 2025, the Security Action for Europe (SAFE), formally the Reinforcement of the European Defence Industry Instrument, is the first pillar of the European Commission’s ReArm Europe Plan/Readiness 2030. It is a core component of the EU’s ambition to mobilise up to EUR 800 billion in additional defence spending. SAFE will make EUR 150 billion in loans available to member states between 2025 and 2030 to support joint procurement of essential defence equipment produced within the EU.
Designed under Article 122 TFEU in response to a fragile security environment, the instrument allows member states to access EU loans at favourable interest rates, with pre-financing of up to 15 per cent. This creates fiscal space for increased defence spending while preserving compliance with EU procurement rules and industrial policy objectives. SAFE also allows for the limited procurement of non-EU components, capped at 35 per cent of total costs, and enables participation of closely aligned third countries under specific conditions.
While this framework signals a degree of openness, it also embeds significant constraints. The 35 per cent threshold and the requirement for EU design authority pose particular challenges for non-EU partners. In practice, transferring full design authority can be challenging due to the proprietary data and technical knowledge embedded in existing systems. If these conditions prove inflexible, SAFE risks limiting third-country participation while simultaneously constraining the EU’s access to readily available capabilities, with potential consequences for interoperability.
Notably, SAFE introduced enhanced participation options for countries that have concluded a Security and Defence Partnership with the EU. Canada successfully negotiated such terms. Negotiations with the UK, by contrast, ultimately failed.
Why the negotiations collapsed
On 18 September 2025, the Council authorised the opening of negotiations with the UK on participation in SAFE. The Commission was to negotiate on behalf of the EU, with the aim of defining the conditions under which UK firms and products could be included in procurement under the instrument.
Negotiations broke down in the final stages over financial contributions. The EU reportedly proposed an administrative entry fee of around EUR 6.5 billion, a figure UK officials described as disproportionate and politically unjustified. London countered with offers in the millions rather than billions. Although both sides adjusted their positions, the gap remained too wide to bridge before the 30 November deadline.
UK Minister for EU Relations Nick Thomas-Symonds described the outcome as “disappointing” but emphasised that British firms could still participate under standard third-country rules, within the 35 per cent threshold. This arrangement falls short of the enhanced role the Starmer government had sought for the UK defence industry.
Sense, Sensibility, and Asymmetries
From a UK perspective, the SAFE negotiations exposed enduring sensitivities around sovereignty, value for money, and post-Brexit positioning. The Starmer government approached the talks with a clear political constraint: any arrangement perceived domestically as “paying to rejoin” EU structures was likely to provoke significant parliamentary and media backlash. The proposed EUR 6.5 billion entry fee, therefore, became politically toxic, regardless of the potential long-term industrial benefits. In London, meanwhile, the figure was framed not as a contribution commensurate with access, but as an implicit penalty for Brexit that undermined the narrative of a pragmatic reset.
There was also a deeper concern about asymmetry. UK officials questioned whether SAFE participation would meaningfully shape EU procurement priorities or merely subordinate British firms to EU-led industrial strategies. Given the UK’s existing defence-industrial strengths and its dense network of bilateral partnerships, particularly with the United States, Italy, and Japan, policymakers were wary of accepting constraints that could limit export flexibility or dilute national control over sensitive technologies.
At the same time, the UK’s negotiating stance reflected selective engagement rather than wholesale reintegration. London sought access to specific instruments that aligned with national capability gaps and industrial interests, without committing to broader financial or governance obligations. This approach, however, collided with the EU’s institutional logic, which privileges comprehensive frameworks over à la carte participation.
Ultimately, SAFE revealed a mismatch between UK expectations of a transactional, capability-driven arrangement and the EU’s view of defence instruments as vehicles for deeper integration. The failure was therefore less about the headline fee than about unresolved differences over what post-Brexit defence cooperation should look like in practice.
What’s next for EU-UK strategic relations?
From a Brussels perspective, the SAFE negotiations underline the persistence of structural constraints that political goodwill alone cannot overcome. Defence and industrial policy sit at the core of the EU’s strategic autonomy agenda, where legal frameworks, collective oversight, and internal cohesion take precedence. Concerns about cherry-picking remain influential, particularly among member states wary of granting extensive access without reciprocal obligations.
France has been among the strongest advocates of strict conditions for third-country participation, reflecting both institutional caution and competitive defence-industrial interests. More broadly, the EU continues to struggle to reconcile its desire for cooperation with the UK with the primacy of EU law and governance structures.
At the same time, there remains a tendency in Brussels to view the UK through an outdated Brexit lens, overstating the risk of engagement while underestimating the strategic cost of exclusion. SAFE illustrates how this tension plays out in practice.
From the UK side, SAFE reinforced a growing perception that Brussels continues to conflate defence cooperation with broader questions of political alignment and regulatory control. While London recognises the EU’s need to safeguard its legal and industrial frameworks, there is frustration that defence—an area of shared strategic urgency—is still filtered through post-Brexit anxieties. UK policymakers increasingly argue that this approach underestimates the costs of exclusion at a time when European security demands rapid capability generation rather than institutional purity.
Domestic political framing plays a central role here. The Starmer government has sought to recalibrate relations with the EU without reopening divisive debates about sovereignty or formal reintegration. Defence cooperation is politically viable precisely because it is seen as pragmatic and interest-based. However, when cooperation is tied to large financial contributions or perceived oversight by EU institutions, it risks crossing a domestic red line. This explains the government’s emphasis on NATO, bilateral frameworks, and flexible coalitions as safer vehicles for engagement.
There is also a sense in London that the EU underestimates the UK’s alternatives. While exclusion from SAFE is undesirable, it does not leave the UK without options. Participation in AUKUS, the Global Combat Air Programme (GCAP), and deepening bilateral ties with European partners provide parallel avenues for industrial collaboration. This reduces London’s incentive to accept unfavourable terms, even at the cost of reduced EU integration.
In this light, SAFE has sharpened the UK’s preference for modular, project-based cooperation over comprehensive EU frameworks. The challenge moving forward will be whether Brussels can accommodate this preference without undermining its own governance principles.
Looking Ahead
The collapse of the SAFE negotiations represents a setback, but not a definitive rupture. Talks could resume in future funding rounds, and both sides have signalled continued willingness to cooperate in other areas. The broader reset remains intact, even if its most ambitious defence-industrial expression has stalled.
From the EU’s perspective, the challenge lies in balancing strategic autonomy with pragmatism. Meaningful UK participation may ultimately require greater flexibility than Brussels has so far been willing to concede. The rapidly shifting global order increasingly calls into question the assumptions that shaped post-Brexit relations.
While progress will remain uneven, the SAFE episode clarifies where cooperation is structurally difficult and where it may still advance. Moving from a reactive to a proactive European security posture will likely require re-evaluating not only relations with third countries, but also the internal constraints embedded in EU defence governance.
Moving forward, the UK perspective suggests that meaningful progress will depend on narrowing the gap between political ambition and institutional design. Cooperation is most likely to advance in areas where mutual dependency is clear, timelines are urgent, and governance requirements can be kept light. Capability development, interoperability standards, and joint support for Ukraine remain politically feasible domains, particularly when pursued through NATO-aligned or ad hoc mechanisms rather than EU-exclusive instruments.
For London, future engagement with EU defence initiatives will be judged against three criteria: strategic added value, industrial autonomy, and domestic political sustainability. Instruments that impose high upfront costs or require extensive regulatory alignment will face resistance, while those offering clear capability gains and export opportunities are more likely to gain traction. This suggests that smaller-scale pilot projects or opt-in modules could serve as confidence-building steps after the SAFE setback.
At the same time, the UK will continue to calibrate its EU engagement within a broader global defence posture. The government’s emphasis on the Indo-Pacific, transatlantic ties, and advanced technology partnerships means that Europe is no longer the sole or even primary frame of reference. This does not diminish the importance of EU cooperation, but it does place it in a more competitive landscape.
Ultimately, SAFE clarifies that a durable reset will not emerge from symbolism alone. From the UK perspective, cooperation must respect post-Brexit political realities while delivering tangible security outcomes. Whether the EU is willing—or able—to adapt its defence instruments accordingly will shape the trajectory of EU-UK security relations in the years ahead.
