How should Britain step up to enhance European security?
The Big Ask | No. 12.2025
Since Donald Trump, President of the United States (US), returned to the White House, the European security architecture is facing increasing uncertainty. While the rhetoric and actions of the US are testing the transatlantic relationship, it is a continuation of America’s longstanding desire to divert resources to the Indo-Pacific and a sign of the superpower’s growing exasperation towards European defence free riding. But, with a resurgent Russia to the east and a transactional US to the west, Europe finds itself in the worst geopolitical environment since the Cold War.
It is therefore unsurprising that European governments are starting to get serious about their own security. With the United Kingdom’s (UK) comparatively sizeable defence expenditure, history of coalition building and, more recently, its firm support for Ukraine, it is placed at the forefront of this new era of European security. So, in this week’s Big Ask, we asked nine experts: How should Britain step up to enhance European security?
Research Fellow on National Security, Council on Geostrategy
Britain should step up to enhance European security firstly by asking where it is in its interests to do so, and secondly by rediscovering the approach it took to grand strategy before the 20th century. Prior to the First World War, London pursued its interests by using its naval power, financial depth and manufacturing capacity to support its allies. This is the approach, one much more grounded in the pursuit of British interests, which the UK should take once more.
By investing in its industrial capacity and in the research and development of new military technologies, Britain will be able to support its allies with the equipment they need and strengthen its own fiscal standing simultaneously. His Majesty’s (HM) Government should aim to have its foot in the door of as many defence markets as possible, recognising that compromise is necessary to do so, but also that there are limits on what caveats the UK should be willing to accept for market access.
Further to this, Britain should prioritise the reconstitution of its naval and air power, although that does not mean the wholesale abandonment of land forces. It is these domains in which the UK can add the most value to those it may choose to fight alongside in the future (these partners can provide the bulk of any land forces), both within the North Atlantic Treaty Organisation (NATO) area of operations and beyond. For now, given uncertainty over US commitments to European security, efforts to reinforce the credibility of NATO’s Article Five should take precedence over other long-term commitments beyond the alliance.
Executive Editor, Internationale Politik Quarterly and Internationale Politik
From Berlin’s vantage point, the UK has already done well when it comes to enhancing European security. The strong leadership shown by Sir Keir Starmer, Prime Minister, after the infamous Oval Office clash between Trump, JD Vance, Vice President of the US, and Volodymyr Zelenskyy, President of Ukraine, has been much appreciated.
What Britain has been doing with Nordic and Baltic partners in the Joint Expeditionary Force (JEF) – increasing deterrence in Northern Europe – is appreciated too. It is a valuable blueprint for closer cooperation and possibly part-integration of European forces. Friedrich Merz, Chancellor-in-waiting of Germany, seeks talks about Britain’s nuclear deterrent, which would certainly be useful. However, British-German cooperation on strengthening conventional deterrence along NATO’s eastern flank may be a more urgent topic to discuss. The bilateral 2024 Trinity House Agreement was an excellent start in forging closer UK-German defence ties, and should be built upon.
HM Government also took the lead when it announced plans to increase defence spending to 2.5% of Gross Domestic Product (GDP). Since last week’s momentous Bundestag decisions, marking a spectacular German U-turn on fiscal policy and allowing for unprecedented borrowing to finance German rearmament, it is now clear that Germany will step up in this regard too. It will now be of utmost importance to include Britain (and Turkey) in European Union (EU) schemes to underpin the strengthening of Europe’s military financially. An EU-UK agreement in form of a special Defence and Security Partnership should pave the way and allow British access inter alia to the EU’s €150 billion Security Action for Europe (SAFE) fund. Circumstances might be dire, but in all this lies the chance of a new beginning.
Director, Geopolitics and Security Studies Centre
Lithuania sees the UK as an essential security partner. The military presence in Estonia is a case in point. Britain’s role in the ‘coalition of the willing’ – the nations supporting Ukraine – is highly valued, especially following the challenges of Brexit.
The possibility of the UK leading a European military presence in Ukraine could once again strengthen ties across the continent, which must build its future on unity rather than fragmentation. Additionally, Britain has a crucial role in maintaining the transatlantic relationship, even though much of that responsibility depends on the US.
The future of European security architecture hinges on European powers taking greater responsibility, providing resources both to Ukraine and towards strengthening the eastern flank. The UK’s role in nuclear deterrence remains solid. However, concerns persist over the shrinking size of the British Armed Forces, which may make it difficult to take on additional commitments.
One promising opportunity is the JEF. While it is still defining its role within the security architecture, it could become a valuable strategic tool – especially if Ukraine is involved.
Senior European Security Analyst, Polish Institute of International Affairs
There is no need for the UK to become more involved in strengthening European security, because Britain’s commitment in this area is already unwavering and significant. One need only mention the £7.8 billion pledged for military assistance to Ukraine and the training of over 50,000 Ukrainian soldiers in Operation INTERFLEX. The recent London Summit on Ukraine, which brought together a broad coalition of EU states, Canada, and Turkey, only confirms the UK’s significant presence at the political level – both in regards to resolving the war in Ukraine and to strengthening European security in the face of uncertainty over US foreign policy.
Poland and the UK have a long tradition of defence cooperation, as evidenced by the start of negotiations on a new UK-Poland treaty in January this year. Working together to protect against Russian aggression and strengthen NATO’s eastern flank, as well as to combat hybrid threats – including disinformation and people smuggling – is crucial from Poland’s perspective, and is exacerbated by the current international situation. Common goals in these areas will give both countries a stronger voice, which could facilitate further practical proposals for European defence cooperation and support for Ukraine, and a view to a lasting peace agreement with Russia.
Associate Director, Centre for Britain and Europe, University of Surrey
In the wake of the transatlanticist nightmare, Britain needs to face head-on the realisation that Charles de Gaulle was unfortunately correct, and begin to take on such Gaullist lessons both internally and externally in its relations with Europe.
This does not mean becoming subservient to a French outlook on European security, but taking US-dominated security arrangements such as the Five Eyes intelligence sharing group and NATO at arm’s length, and engaging more constructively in EU-led efforts as well as non-EU related European security efforts. The name of the game now is hedging, and all of Europe would benefit from the UK being more liberal and transactional with its European security capabilities.
Franco-British relations here are key, not least because the rest of Europe depends on the UK being able to speak hard truths to our French colleagues. Few others are able to do so from a similar position of power, and while a measure of cap-in-hand corrections will be necessary in these discussions, reigning in some of the more triumphalist Gaullist voices will also benefit the whole of Europe in a constructive and realistic approach to European security.
Europe, it seems, is being left to the Europeans, and Britain’s place within the continent is being rediscovered.
Research Fellow, Finnish Institute of International Affairs
Britain’s capacity to mobilise its forces quickly behind NATO’s Article Five is vital for deterrence in Northern Europe. NATO’s northern and eastern flanks combine a vast geographical expanse from the Arctic to the Black Sea. Reinforcing credible deterrence for these regions centres on NATO’s ability to mobilise large numbers of troops to support forward deployed battlegroups. This mobilisation relies heavily on US military logistics, technology and command and control. In the early tumult of Trump’s second presidency, Washington has acrimoniously commanded European allies to do more to support collective defence and deterrence.
Among NATO’s ‘big three’ European powers (the UK, France and Germany), Britain arguably remains the military power with the most efficient logistics and strongest mobilisation capacity. Enhancing both of these as the US reduces its military assets in Europe will keep Britain ready as a framework nation supporting collective defence in Northern Europe. As doubts surround US reinforcements, Denmark, Finland and Sweden will support stronger EU defence cooperation, but the Nordic states will still look to Britain as an increasingly vital partner. Nordic governments retain realistic hope that HM Government maintains domestic political stability, returns Britain to full economic health and leads by example with increased defence investment – a combination to ensure Britain remains a powerful voice in supporting democratic interests.
Assistant Director, Centre for European Reform
Seen from Rome, the UK is an essential partner and pillar of European security. The UK’s contribution to a stronger European security posture can be both political and practical.
Politically, Italy and the UK currently find themselves on the same page in terms of trying to keep Trump’s America as involved in European security as possible. In that sense, the UK’s ability to engage constructively with the Trump administration and its attempts to defuse conflicts are very valuable. Moreover, the very good state of bilateral relations means that Italy is generally well-disposed towards the UK playing a large role in intra-European diplomacy, helping other European nations coalesce around a common strategic vision of how to ensure European security.
Practically, Italy sees the UK as an essential element of a stronger European deterrence posture. There is ample appetite to work together more, with Italy and the UK working together on the Global Combat Air Programme (GCAP) next generation air platform, among other common defence projects. Italy is keen on deepening cooperation and is a strong proponent of bringing the UK as close as possible to the emerging EU defence ecosystem. However, there are doubts about what the UK can currently contribute to European deterrence in terms of land capabilities. If the Strategic Defence Review (SDR) leads the UK to focus more on Europe and less on Asia, Italy would welcome that.
George Scutaru
Chief Executive Officer, New Strategy Centre
Europe must ensure that the negotiations regarding the peace process in Ukraine will conclude with a robust agreement guaranteeing Russia will not attack Ukraine again. If we only have a ceasefire which has been negotiated easily and superficially by the US, Vladimir Putin, President of Russia, will attack Ukraine again within three years to destroy the country. But, Putin cannot destroy Ukraine as long as it maintains access to the Black Sea. Therefore, his objective in the event of a new attack will be to occupy the entire coastline up to Mount of the Danube.
Even during a ceasefire, we could see Russia occupying Snake Island, which is close to the mouth of the Danube and between the corridor from Odesa to Istanbul. The UK must get involved in ensuring the security of the Black Sea, maintaining its free and open status, and one of its objectives should be to prevent Russia from capturing Ukraine’s coastline and Snake Island.
Alongside France, the UK must also discuss providing a nuclear umbrella for Europe, complementary to what the US currently offers.
The main objective must be a policy of deterrence towards Russia, especially given America’s declining interest in Europe.
Programme Director for Security Studies, Centre for Defence Strategies and Joint Programme Leader, Future of Ukraine Programme, Centre for Geopolitics, University of Cambridge
The increasingly unpredictable position of the US under the second Trump administration has made it clear that Europe can no longer rely solely on Washington to underwrite its security. As NATO faces unprecedented strain, the UK has both the capacity and the strategic opportunity to help anchor a new European security framework.
Britain’s nuclear deterrent and advanced military capabilities place it among the few European nations capable of projecting credible force at scale. Its recent discussions with allies on deploying up to 30,000 troops to Ukraine show a growing consensus around the need for a Euro-Atlantic military presence that goes beyond arms transfers.
Recent initiatives by Sir Keir, including his pledge to raise defence spending to 2.5% of GDP by 2027, with an ambition to reach 3% by 2030, are essential first steps. But rhetoric must now be matched with systemic leadership and action. Britain should take the lead in organising, training and equipping multinational rapid-response forces to deter further Russian aggression. The idea floated by Sir Keir at the coalition of the willing summit last week for a peacekeeping force of over 10,000 troops could serve as a cornerstone for this effort.
Furthermore, British leadership is vital in pushing Europe to overcome its own fragmentation. This is particularly true in joint munitions production and technological cooperation, with advanced technologies still being developed nationally across the continent. By helping to catalyse a more coordinated European defence industrial strategy, the UK can ensure that Europe develops the economic deterrence and technological depth necessary to counter adversaries.
The rhetoric and actions of the Trump administration, and the alarming speed at which this transformation is taking place, means that the final test for Europe – including the UK – will be how fast it can fully integrate Ukraine (not only in terms of interoperability and joint military training) into European security frameworks.
Ukraine is the ultimate test of Europe’s – and Britain’s – strategic seriousness. UK support should move beyond arms provisions to include long-term security guarantees, defence sector investment and reconstruction aid, the training and modernisation of Ukraine’s armed forces, and active participation in shaping pathways to Ukrainian membership in NATO and the EU.
Britain’s leadership at this decisive moment can demonstrate that it is not merely reacting to global instability, but shaping a new European security order grounded in resilience, cooperation and strategic foresight.
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What do you think about the perspectives put forward in this Big Ask? Why not leave a comment below?
Hi, Ben. Any thoughts on Britain’s recent exclusion from the €150bn European rearmament fund?