The United Kingdom's Strategic Defence Review: The Challenge of Turning Ambition into Action

When the Strategic Defence Review (SDR) landed on the desks (of those who received a printed copy) on June 2, more than 300 days after it was commissioned, it ended several months of leaks and speculation about the future of the United Kingdom’s Armed Forces. This SDR is one of the most extensive documents of its kind in recent UK history. It will take time to clearly understand the implications of its 62 recommendations – and this article does not aim to cover them all – but at first glance, some ideas stand out regarding the central theme: the military capability of the United Kingdom.

Network-Enabled Capability for the 2020s

First, this Review is truly ambitious. It proposes a vision to transform the construction, management, and deployment of the United Kingdom’s Armed Forces. To achieve this, a shift towards a combination of high and low-level capabilities is essential, recognizing that our current forces, while highly capable in some respects, are too small and costly to provide sufficient combat power, and are likely to be precarious if used in modern industrial warfare.

Technology will be an important part of the solution, partially compensating for low numbers with greater firepower, and connecting the various forces to create an “Integrated Force” that is greater than the sum of its parts, capable of operating with focused violence when necessary. For those with good memories, it will likely resemble an updated version of the Network-Enabled Capability ( Network-Enabled Capability) concept, similar to the U.S. concept of Network-Centric Warfare (Network-Centric Warfare) from the 2000s, and popularized in the UK following the2003 SDR New Chapter. Making better decisions more quickly is at the heart of this transformation, and the Review also proposes enhancing forces with longer-range weapons, better sensor and communication networks, and a greater proportion of unmanned systems. This is largely based on the experience of Ukraine, and it is legitimate to question whether too much emphasis is being placed on a particular war. However, the counterargument is that the underlying ideas have broad support in analyses from other areas (including previous work

by RUSI ). The SDR also proposes a systemic change in the use of technology that allows for more data collection, better utilization, and attention to the analysis of the role of drones, considering them a vital capability, but not a panacea. TheReview

highlights the importance of digital networks, space capabilities, and processing power, rather than simply calling for flashier weapons, such as lasers (there are some, although not mounted on sharks). Furthermore, it does not propose a single effort to catch up, but argues that constant innovation must be part of the routine Defense activity, as a necessary measure to keep pace with technological advancements. Rebuilding the Foundations Also Matters But the SDR is not just about

Vorsprung durch Technik

(progress through technology). To begin with, it opposes further reductions in personnel and replacing them with better missiles or more drones; rather, it proposes increasing the number of personnel, prioritizing the Army. The caveat is that this is contingent on “when funding allows,” and even then, the Armed Forces will be worryingly small compared to the casualties and losses that could be expected in a major industrial war. The Review

is realistic about the measures that can be taken in this scenario, working with the forces as they are. The future will not be dominated by “small robots,” relegating people to maintenance tasks . It also addresses fundamental issues: recruitment of personnel, housing, infrastructure, industry, links with society, and reserves of supplies. It pays timely attention to reserve forces, medical services, command and control, and space, proposing some significant changes to the structure and functioning of Defense. For this rapid development to work, a completely new approach to innovation and the relationship with industry will be needed, along with a recognition that NATO should set more requirements for the United Kingdom, combined with a much more directed approach to building the Armed Forces. If the language used so far regarding integration wasa bland and linguistically tortuous mishmash

, this SDR is more direct regarding the creation of a single force, designed from the top down. In fact, reading the arguments presented by those who led theReview , it is clear that they consider a deep reform of almost all aspects of Defense necessary for the Armed Forces to be “ready for war.” The SDR, likely wanting to avoid alarmism, downplays this concern, but the implication is clear: assuming this is what is needed to be ready for modern warfare, thenthe United Kingdom is falling far behind . Ambiguity is a Threat to the Implementation of theReview

If this sounds like a resounding endorsement of the SDR, now comes the harsh reality and a touch of skepticism: the difficult part is realizing the changes, and in this respect, the Review

has scant details on how these ideas will be implemented in many areas. For example, after multiple failed attempts at reform, particularly in procurement, what is different this time? The Review

continues the recent trend of dismantling the Levene Reforms , which aimed to address the recurring problemsof culture and coordination in the Armed Forces, and which were part of an almost continuous process of “fixing” the efficiency and speed of capability acquisition. The new “alliance with industry” has ambitious goals to accelerate procurement. These goals will require not only a significant cultural change within the Ministry of Defence (something the system has always struggled with), but also a change of similar magnitude in the processes and mindset of defense industry partners. The Review

includes a series of objectives in its recommendations, but these mainly refer to establishing institutions and processes, for example, a new approach for industry defined for March 2026, or a new training policy for January 2026. Some capabilities have concrete targets, such as the new “Digital Targeting Web” that will be operational “in 2027,” but many other sections are ambiguous, and certainly do not include sufficiently ambitious objectives to drive an accelerated pace and imaginative solutions. For instance, what does it mean to multiply by ten

the “lethality” of the Army? The current Chief of the British Army has already expressed his ambition to double the Army’s combat power by 2027 , and double it again by 2030, but it is unclear how these two objectives relate to each other, or what the timeline is. The composition of forces that the Royal Air Force should have as it increases the use of unmanned systems is not described, and integrated air and missile defense receives £1 billion without providing details on the objectives to be achieved. Curiously, the Reviewindicates that the precise figure of 7,000 new long-range weapons will be acquired, along with the construction of six new factories, but does not provide information about these factories or weapons. The danger lies in the fact that, in the absence of more specific benchmarks (some of which, according to the Review

, the Ministry of Defence can unilaterally define), there is a wide margin for “transforming” the Armed Forces. Cultural inertia and internal competition in Defence have hindered previous attempts to implement the necessary changes. The Reviewargues, with some justification, that there should not be a “rigid force design with a specific delivery date,” as it will be necessary to continue evolving. Previous reviews

have also provided varying levels of detail on objectives. But in this case, in the absence of individual objectives or a qualitative judgment on a target for the Armed Forces, almost any perceptible change, or even an existing initiative presented in a different way, could be considered a “transformation.” Some information known prior to the SDR already shows existing tensions, in that the Review does not provide details on the supposed size of the Royal Navy and the role of the Royal Air Force in nuclear deterrence . It is easy to suspect political influence in this case, reporting what they would like the conclusions to be, rather than what the Reviewactually said (or what the Treasury could fund). It is not all about money, but it helps Resources remain a problem as well. Members of the

Review

team have argued that reaching 2.5% of GDP for Defence by 2027, and 3% by the early 2030s, means that this is feasible , and they explicitly state that it is the only way to achieve the program. However, the increase to 2.5% of GDP will provide “only” about £6 billion additional per year, and even assuming that after 2027 there will be a pronounced increase in funding to reach 3%, full implementation could entail a very high cost.The Review

claims that it is realistic to assume that through greater efficiency, around £6 billion will be saved (almost the only identified compensatory reduction). But previous experience suggests caution: the 2015 Strategic Defence and Security Review of the National Security Strategy also contained optimistic savings projections, which the then Chief of the Defence Staff, Nick Houghton, later admitted were the result of a ” collective self-deception “. There is no updated public data available on the status of the existing equipment plan, but theearly retirement of a number of capabilities in November 2024to save £500 million over several years suggests that there are still significant pressures, especially regarding nuclear projects. Therefore, accelerating transformation or making more significant changes before 2027 will likely require greater cuts or savings in other areas. Hope is not a strategy, and neither is the SDR Fundamentally, the SDR provides direction, not strategy. It does not say much regarding planning assumptions, justification for the use of forces, or prioritization (beyond “NATO first”). It avoids explicitly referring to the more complex dilemmas – likely to leave them in the hands of the Ministry of Defence – or setting overly challenging objectives, which carries the risk of the system having too much freedom of action. The long time it took to develop – likely due to

financial disputes

– does not inspire optimism about long-term funding, no matter how confident the Review team appears. Additionally, the current debate in NATO is likely to intensify pressure to increase spending, although it may also require even more accounting juggling. A more comprehensive analysis of the Review could question whether the geopolitical context is being treated realistically, especially as it addresses the relationship with the U.S. as if it were going through a normal period, in contrast to what some members of the Review team have said subsequently . Perhaps this demonstrates a lack of consensus, or a reserved approach, but it could also leave work to be done for the next National Security Strategy. It would also be worth analyzing its attempts to improve the resilience of the United Kingdom. This is not intended as a disrespectful critique of the Review , which included a broad consultation process (even with several members of RUSI), and it is understandable that years of partial or failed reforms generateskepticism

about the fate of its recommendations. Furthermore, it is important not to judge the SDR based on unrealistic expectations regarding precise details. However, it is fair to compare its statements with what both its authors and the Government claim it can achieve. This Reviewset out to break the comfortable consensus that had led to “hollowing out” and prepare the United Kingdom to wage a major war; it is reasonable to ask when it should be ready for that war, and how it will achieve it. All eyes will now be on the Defence Investment Plan and the implementation of the Review by the Ministry of Defence. If Defence truly reforms and implements the ideas of the SDR swiftly, enthusiastically, and with resources, this could mark a turning point in the military capabilities of the United Kingdom. But if the usual inertia and budgetary instability prevail, the Review

may be remembered primarily for what it failed to drive forward. Reprinted with permission from the Royal United Services Institute (RUSI) . The views expressed in this commentary are those of the author and do not represent those of RUSI or any other institution.