The latest Strategic Defence Review marks a significant moment in articulating the United Kingdom’s response to contemporary security challenges and in shaping its broader role within global security. In this forum, members of the Global Disorder Research Group offer critical, interdisciplinary reflections on the Review, examining its assumptions, priorities, and implications. The contributions engage with ongoing debates concerning the future of defence policy, the changing character of warfare, and the complex interplay between domestic politics, security, diplomacy, and global disorder.

Inderjeet Parmar: UK Strategic Defence Review Militarises Society, Subordinates UK to US Power, and Escalates International Tension

Its emphasis on expanding reserve forces, and on “whole-of-society” resilience normalises military priorities, echoing US-led doctrines of perpetual readiness. Its “whole-of-society” approach includes a UK Strategic Reserve by 2030 and a 30% expansion of cadet forces, embedding militarisation deeper into civic life, echoing ‘total war’ strategies. Proposed recruitment drives, defence industry apprenticeships, and mobilisation of broader public opinion, foster a culture of fear-based national security. This mirrors other European powers’ efforts bolstering conscription and defence budgets, aligning with NATO’s escalating ambitions.

In practice, the SDR has also shaped the threat-based analysis in the subsequent 2025 UK National Security Strategy The NSS, as demanded by President Trump, states a UK commitment to increasing annual military spending to 5% of GDP.

The SDR further integrates AUKUS, particularly through nuclear-powered submarines and advanced technologies like AI and hypersonics. By prioritizing a “New Hybrid Navy” and industrial cooperation, the Review strengthens a China-containing Indo-Pacific partnership led by the United States. However, funding uncertainties suggest Britain’s inability to meet AUKUS commitments, potentially further relegating it to a junior partner of the US.

For Five Eyes (UK, US, Canada, Australia, New Zealand), the SDR’s emphasis on cyber and intelligence capabilities bolsters the alliance’s role in countering hybrid ‘threats’. Enhanced UK investment in signals intelligence and joint exercises aligns with Five Eyes’ intelligence-sharing ethos, critical for NATO’s Euro-Atlantic focus. Yet, the SDR’s pivot toward European security is in tension with Five Eyes’ broader global mandate.

The SDR’s “whole-of-society” militarisation strategy represents a new phase in the era of geopolitical competition, and the likelihood of a new arms race. How will this influence public support for the strategy? Only time will tell. The SDR’s alignment with US strategic priorities strengthens NATO, AUKUS and Five Eyes, but further entrenches Britain in US-led confrontations in a volatile multipolar world, including an unreliable and unpredictable US strategy under President Trump.

Michael Ben-Gad: When Funding Allows: Defence Planning for 2035 in a 1939 Moment

As the report states:

While the Ukraine conflict has temporarily degraded Russian conventional land forces, the overall modernisation and expansion of its armed forces means it will pose an enduring threat in key areas such as space, cyberspace, information operations, undersea warfare, and chemical and biological weapons. Russia’s war economy, if sustained, will enable it to rebuild its land capabilities more quickly.

The emphasis is on meeting European challenges, referred to in the document as ‘Nato first.’ Largely gone is the rhetoric about Britain punching above its weight and the goal ‘to shape the global security environment’ though mentioned, is clearly deprioritised.

This change reflects an implicit recognition that as its share of global GDP continues to shrink, Britain can no longer act independently as a major power beyond its immediate environs. Furthermore, As the United States shifts its focus to Pacific its willingness to defend its NATO allies will continue to wane. The era of European free-riding on US defence spending is likely ending. Britain must now prioritise defending itself and its nearby allies from the growing Russian threat.

This has implications for the shape of British forces. If US commitment to Europe is ebbing, there is less rationale for the UK to maintain forces designed to complement American operations elsewhere. Britain built two aircraft carriers in part to enable it to contribute to US-led operations around the world. But if the US can no longer be relied upon to protect the UK and its other European allies, the logic of such force structures collapses. The old quid pro quo—supporting US missions (in Afghanistan and Iraq) in return for American security guarantees—may no longer hold.

The broader strategic danger lies in the possibility of a coordinated assault by authoritarian regimes—China, Russia, Iran, and North Korea. A polycrisis scenario could see simultaneous moves: China blockading Taiwan, Russia advancing into the Baltics, Iran attacking Israel or Saudi Arabia, and North Korea threatening South Korea. Such a sequence would force the United States to either prioritise one theatre or split its forces, potentially overwhelming the West.

Yet such coordination is not even necessary. China could initiate a blockade of Taiwan in the next year or two, prompting a major US military response. That, in turn, could present Russia with an opportunity to push westward while American attention is elsewhere.

This brings us back to the underlying contradiction in the review: though it is clear on the threats, the steps outlined do not reflect the scope or immediacy of the challenge given the current state of the UK’s forces. From the House of Commons Defence Committee, 14 March 2021:

….were the British army to have to fight a peer adversary—a euphemism for Russia—in Eastern Europe in the next few years, whilst our soldiers would undoubtedly remain amongst the finest in the world, they would, disgracefully, be forced to go into battle in a combination of obsolescent or even obsolete armoured vehicles, most of them at least 30 years old or more, with poor mechanical reliability, very heavily outgunned by more modern missile and artillery systems and chronically lacking in adequate air defence. They would have only a handful of long-delayed, new generation vehicles, gradually trickling into the inventory, to replace them.

Anticipating that war was perhaps inevitable, Britain not only increased defence spending but reintroduced military conscription in April 1939 in reaction to Hitler’s invasion of Czechoslovakia in violation of the Munich accords signed six months earlier. Russia invaded Georgia in 2008, Ukraine in 2014 (in violation of the Budapest Memorandum of 1994) and again in 2022. One might ask if the following convey a sense of urgency (emphasis is mine):

Page 5: “On 25 February 2025, the Prime Minister announced the largest sustained increase to defence spending since the end of the Cold War—rising to 2.5% of GDP by 2027, and to 3% in the next Parliament when fiscal and economic conditions allow.”

Page 10: “What is also significant is the ambition to spend 3% of GDP on defence in the 2030s if economic and fiscal conditions allow.”

Page 18: “Overall, we envisage an increase in the total number of Regular personnel when funding allows. This includes a small uplift in Army Regulars as a priority.”

Page 18: “Increasing the number of Active Reserves by 20% when funding allows (most likely in the 2030s)…”

Overall the term ‘funding allows’ appears ten times.

As in much of the western world, the population is aging and ever more dependent on government spending on welfare and healthcare. In the UK, taxes now account for 36.4% of GDP but is insufficient to cover the full cost of government expenditure—public sector net borrowing is 4.5% and interest payments on the accumulating debt 3.7% of GDP. Though the government has not reached the upper limit of what it might conceivably raise in taxes or borrow, as these limits draw closer, the negative impact on the economy will become ever more pronounced. The message of the strategic review is that the international situation may be darkening, but the UK will continue to prioritise domestic concerns and hope for the best.

Francesco Rigoli: The price of militarization: the Strategic Defence Review should not neglect the economic, strategic, and cultural costs of rearmament

Second, the policies advocated by the Review may, paradoxically, predispose the British state to rely on military force instead of diplomacy, and may encourage other states to do the same. If the UK wants to play a leading global role, promoting diplomacy rather than military confrontation may be more fruitful, but the Review signals that the UK has chosen to stress military prowess rather than betting on diplomacy. The Russian attack on Ukraine has changed dramatically the West’s perspective on diplomacy. While not long ago diplomacy was considered to be the only acceptable tool, today diplomacy is often dismissed by the West as unrealistic, especially in dealing with Russia. This view is understandable, but it should not be accepted uncritically. Although, at present, finding a diplomatic settlement with Russia is difficult and would require unpalatable compromises, the alternative of a never-ending war with the potential of a dramatic escalation is no more desirable. There is little to no discussion in the Review about how its suggested measures may undermine diplomacy as a tool for managing global conflict.

Finally, one should not ignore the psychological and cultural consequences that may ensue if the Review’s recommendations are implemented. Militarising society may imply that the public discourse will increasingly emphasise aspects such as threat, aggression, and intolerance of diversity, potentially leading to a more authoritarian climate.

All in all, this commentary is not a sweeping attack on the Review but, rather, an invitation to have a balanced discussion about its costs alongside its benefits. Only a clear understanding of such costs can tell us if militarising the British society is really the best course of action.

Begum Zorlu: The UK’s 2025 Strategic Defence Review and the Centrality of Threat Framing

The review shows how the current government aims to position security as the fundamental organising principle of governance, supported by Keir Starmer’s opening statement that “national security is the foundation” of the government’s strategy.

Looking across the review, its repeated focus on “whole-of-society” mobilisation (mentioned over 20 times) stands out as a significant shift towards militarisation. Yet what emerges most clearly from the document, and provides the rationale for this shift, is the centrality of threat framing as an organising logic, with every major policy recommendation flowing directly from assessments of adversarial capabilities and intentions.

The review is based on the assertion that Britain faces such profound threats that preserving the current situation is no longer feasible, necessitating comprehensive change. While it recognises challenges like terrorism and demographic shifts, it highlights Russia and China as the main threats influencing the UK’s defence policy.

The document uses temporal indications to distinguish different levels of urgency for various threats. Russia is presented as an immediate threat actively attacking the UK through espionage, cyber-attacks, nuclear threats, and information manipulation. China, meanwhile, is described as a “sophisticated and persistent challenge,” indicating a longer-term pressure that demands ongoing preparedness for strategic competition. These distinctions support both short-term solutions and long-term transformation justified by the urgency framing. Additionally, the emphasis on urgency elevates the overall security situation above usual political cycles.

The focus also presents authoritarian coordination among these states’ leadership as a challenge to what has been called the rules[2]-based international order. It justifies its “NATO First” strategy as crucial for maintaining the global system underpinning Britain’s security. Instead of viewing Russia, China, Iran, and North Korea as isolated regional concerns, the document explicitly links them through a pattern of authoritarian cooperation. By emphasising these increasing connections, the review consolidates various security threats into a single, unified threat that requires a comprehensive response.

Nuclear modernisation also exemplifies threat-driven policy, as major investments in new warheads and submarines stem from concerns that Russia and China prioritise nuclear weapons in their security strategies and are quickly growing their arsenals.

Another important part is that the review’s technological transformation plan is directly based on this threat assessment. It highlights worries about artificial intelligence and autonomous systems, particularly in relation to China’s technological progress. The document cautions that Britain might encounter Chinese technology in any conflict or with any opponent. This view shifts innovation focus into a survival mode, making technological progress essential for staying relevant in future conflicts.

Yet this heavy emphasis on technological solutions exposes both contemporary anxieties and potential strategic vulnerabilities. The review repeatedly portrays innovation, artificial intelligence, and autonomous systems as decisive in future conflicts, promising that technological progress will restore Britain’s military advantage. Such technological determinism raises concerns about over-reliance on complex systems that may prove fragile in combat, reflecting perhaps unrealistic expectations of what innovation can deliver.

The SDR’s perspective also reveals the constraints imposed by its threat-centric framework. Regions beyond the Euro-Atlantic receive minimal attention beyond scattered references, viewed primarily through narrow lenses of counter-terrorism operations and countering Russian or Chinese influence.

Overall, the SDR demonstrates how threat framing has become the central lens through which British defence policy is articulated, enabling expansive militarisation and technological investment. At the same time, this framing narrows the scope of diplomacy, sidelining issues such as climate change while reinforcing a security agenda defined primarily by great power competition.

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[1] Expeditionary warfare refers to the deployment of a state’s military forces abroad to conduct combat operations in a foreign country.

[2] The “rules-based international order” generally refers to the post-1945 system of international norms, institutions, and practices designed to regulate state behaviour through agreed rules rather than raw power.