One year on from the Strategic Defence Review. Where ambition is no longer enough.

By Imogen Vanhegan-Harris When the Strategic Defence Review (SDR) was published a year ago today on 2 June 2025, it was presented as a decisive reset for UK defence. After years of concern about hollowed-out capability, industrial fragility and an increasingly hostile international environment, the Review offered a clear diagnosis that the UK had entered “a new era of threat” and that a new model of defence was needed.

The Government accepted all 62 recommendations, signalling its commitment to action.

A year on however, the question is no longer whether the Review identified the right threats, but rather whether the UK is moving fast enough to turn ambition into deliverable capability.

The SDR recognised the return of state-based conflict, the importance of NATO and Euro-Atlantic security, the need for stronger industrial resilience, and the growing centrality of cyber, AI and electromagnetic capability. It also placed defence more firmly within the Government’s wider economic and industrial agenda, linking national security to jobs, supply chains, innovation and regional growth.

However, the SDR is only meaningful if its ambition is matched by funding, delivery timelines and the right procurement decisions. One year on, that is where the gap has opened.

The most obvious problem is the continued delay to the Defence Investment Plan (DIP). The DIP is meant to translate the SDR’s high-level ambitions into a funded programme of equipment, technology and capability decisions. It is, in effect, the answer to the question that the SDR left open: what will be prioritised, what will be funded, and what will have to wait?

For the Armed Forces, delays to the DIP cloud clarity on future force design, procurement and readiness. For industry, the delay has more immediate commercial consequences in terms of investment decisions. Defence companies need long-term confidence before committing capital, expanding facilities, hiring specialist workers or scaling production. This is particularly important for SMEs and defence technology firms, which are often central to innovation but less able to absorb prolonged uncertainty. Without a clear investment pipeline, companies may slow recruitment, delay expansion, focus on export markets or consider whether other jurisdictions offer stronger procurement signals.

This is already becoming evident and raised in the House of Commons as a concern. During yesterday’s defence oral questions, Liberal Democrat MP Edward Morello warned that defence firms in his constituency were frustrated by repeated delays, saying some had suggested that “at this rate they will be European or US headquartered by this time next year”. The collapse of Aeralis, the British military aircraft start-up, has also been cited as a warning sign of what can happen when emerging defence companies are left waiting for clarity on future government investment.

For allies, it creates uncertainty over the UK’s ability to deliver on the role it has set for itself within NATO. For adversaries, it risks signalling that the UK can diagnose the problem faster than it can mobilise the resources to address it. As the Chairs of the Defence and Public Accounts Committees warned in January this year, further delay to the DIP risked sending “damaging signals to adversaries”. In the current security environment, pace is itself a form of deterrence. The Defence Committee has also held evidence sessions specifically on the impact of the delay on industry, hearing from organisations including ADS, the Federation of Small Businesses, Make UK Defence and techUK.

The delay also has wider parliamentary implications.

The Armed Forces Bill is progressing through Parliament, currently awaiting committee stage. The Bill can provide an important framework for service life and reform, but without the DIP, Parliament, industry and the Armed Forces still lack a detailed account of how the Government intends to sequence and resource the SDR’s commitments.

This matters because the strategic environment has not paused while Whitehall finalises its plans. Russia’s war in Ukraine continues to demonstrate the centrality of drones, munitions and data integration amongst many other things. The Middle East remains volatile. The UK’s critical national infrastructure faces persistent cyber and hybrid threats. Senior military leaders have also made clear that readiness is a near-term challenge, not a distant aspiration, with Chief of the General Staff General Sir Roly Walker warning that the Army must be prepared for potential conflict by 2027, and First Sea Lord General Sir Gwyn Jenkins setting out a plan to move the Royal Navy to warfighting readiness by 2029. Yet the SDR’s headline ambition of 2035 risks feeling too distant unless there is clearer evidence of near-term delivery.

The political debate is therefore heating up. Opposition parties have increasingly focused on the Government’s failure to publish the DIP, arguing that the SDR has created expectations without yet providing the capital plan to meet them. The Liberal Democrats have called for defence bonds as a way of funding increased investment, while the Conservatives have indicated that they will conduct a “shadow SDR”, with an initial focus on personnel.

Reform UK also cautioned against framing defence investment primarily as an economic growth strategy. Speaking at The Spectator’s National Security Summit 2026, Danny Kruger MP argued that while defence spending can support jobs, factories and industrial growth, its primary purpose must remain national security and resilience. If growth becomes the dominant lens, investment risks being directed towards politically attractive projects rather than the capabilities needed to deter and fight adversaries.

Upon writing this, the Government has now committed to publishing the DIP before the NATO summit in Ankara on 7-8 July. That gives the document added significance. It will not only be read domestically by Parliament and industry, but also by allies looking for evidence that the UK can resource the capability ambitions set out in the SDR and meet the wider spending commitments agreed at NATO.

From just a brief summary here, we can see that a year on, the SDR remains a serious and important document that continues to test government on whether it can move from strategic recognition to practical mobilisation. That test however has not yet been passed, and we await the publication of the Defence Investment Plan to be the key moment. It will show whether the SDR is becoming a funded programme of renewal, or whether it risks joining the long list of defence reviews that identified the problem but failed to change the trajectory.

The SDR set the direction, but now the Government must turn that ambition into pace, funding and visible delivery.