The UK’s long-awaited Defence Investment Plan sets out how the government intends to translate its Strategic Defence Review into concrete investment over the coming decade. While the plan confirms ambitious spending across several priority capabilities, notably deep precision strike, its publication has prompted a mixed reaction over funding, implementation and the pace of modernisation. Those questions extend beyond the United Kingdom, particularly for European partners closely involved in future defence programmes.
The publication of the UK’s Defence Investment Plan (DIP) on 30 June finally provided the financial roadmap that had been awaited since the publication of the Strategic Defence Review last year. Its repeated delays had become a political issue in themselves, fuelling criticism that the government had articulated ambitious strategic objectives without explaining how they would be financed. Lord George Robertson notably labelled this “corrosive complacency”, as the review had highlighted serious gaps in the UK’s armed forces.
The plan certainly contains significant headline figures. Over the next decade, the Ministry of Defence expects to spend £298 billion while increasing defence expenditure towards NATO’s new targets. Prime Minister Keir Starmer described it as a plan to ensure Britain could “fight and win” in an increasingly dangerous world, arguing that the country had to “spend better” rather than simply spend more. The government also presented the package as part of a wider commitment that would ultimately bring national security spending to 4.2% of GDP, according to the outgoing PM. Yet many independent observers have concluded that the document raises almost as many questions as it answers.
Ambitious objectives, uncertain funding
The plan has received both positive and negative reviews. “This is cost-cutting by another name, it’s not an investment plan, it’s sticking plasters,” explained Tom Sharpe, a retired Royal Navy commander, to Defense News, adding that the plan for a hybrid navy was “chronically underfunded.” An extra £4.7 billion is expected to be secured through the 2026 Budget rather than being guaranteed today.
Criticism has not come solely from think tanks. Tan Dhesi, Labour chairman of the House of Commons Defence Committee, welcomed the additional investment but argued that the document contained “significantly less detail” about how this investment will be delivered and added that it was disappointing that we still do not have a clear timeline to reach 3% of GDP, let alone a path towards 3.5% as agreed at NATO.
Not every reaction was negative. NATO Secretary General Mark Rutte welcomed Britain’s contribution ahead of the Ankara summit, saying Allies would soon be signing “massive quantities of new contracts, memoranda of understanding and letters of intent.” Defence industry association ADS similarly welcomed the publication, with chief executive Kevin Craven stating: “We welcome the Defence Investment Plan.”
A European issue as much as a British one
The debate extends well beyond Britain’s domestic defence policy. Many of the programmes highlighted in the DIP depend directly on cooperation with European allies. France remains Britain’s closest defence partner under the Lancaster House framework, while Germany has become an increasingly important partner through the Trinity House agreement signed in 2024.
This is particularly evident in the field of Deep Precision Strike (DPS), which has become one of NATO’s highest priorities following Russia’s extensive use of long-range missiles during the war in Ukraine. European militaries have also recognised that US long-range strike assets cannot automatically be assumed to fill future capability gaps.
The importance of this capability was underlined at the NATO summit in Ankara, where twelve European countries committed to investing more than $50 billion over the next decade in long-range strike capabilities. The UK will lead or co-lead several of the associated capability workstreams, covering air-launched strike, long-range land strike and low-cost precision weapons. “The UK is already working with partners to develop exquisite capability that will give our Armed Forces the ability to defend and deter thousands of kilometres from the front line, but this UK-led initiative will allow us to step up our cooperation, bringing European Allies together to ensure NATO remains safe and secure for years to come,” said the PM. “We must continue to work together as Allies to develop the capability of the future to bolster security and protect growth at home,” he added.
Within that broader framework, the Defence Investment Plan allocates around £1.4 billion to the multinational STRATUS programme, developed with France and Italy as the successor to Storm Shadow. By comparison, the UK’s contribution to the Anglo-German Trinity House missile programme amounts to £770 million over four years. Both figures were confirmed by the government during the Ankara announcements.
The funding differential reflects the relative maturity of the two programmes. STRATUS is already well advanced. Originally launched as the Future Cruise/Anti-Ship Weapon (FC/ASW) programme in 2017 before being renamed in 2025, it is expected to replace Storm Shadow through two complementary variants: a stealthy cruise missile (Low Observable) and a high-speed missile (Rapid Strike). MBDA chief executive Éric Béranger said in March that the programme was approaching the end of its concept assessment phase and that France and the UK had committed to entering development under the Lancaster House 2.0 agreement. Operational service, however, is not expected until the early 2030s. That leaves Britain facing several years in which its long-range air-launched strike inventory will remain limited.
Bridging the gap before STRATUS
That transition period may prove to be the most difficult aspect of Britain’s long-range strike strategy. The Defence Investment Plan makes clear that the Royal Air Force will eventually move away from Storm Shadow, stating that the missile “played a vital role” but that the UK is now “pivoting towards the next generation of lower-cost cruise missiles.” While the official document avoids using the word “retirement”, subsequent government briefings and media reporting have confirmed that Storm Shadow will be phased out over the coming years.
As aforementioned, the STRATUS programme’s in-service date remains, hopefully, in the early 2030s, while the parallel Anglo-German family of long-range missiles developed under Trinity House is expected to arrive even later. The decision to retire Storm Shadow in the near future could therefore prove a bold gamble, given the imminent Russian threat so frequently invoked by British policymakers. It would leave the UK armed forces without a credible deep-strike capability throughout the 2027–2032 period.
Meanwhile, by way of comparison, Ukraine, having demonstrated the system’s operational value, has just secured further British backing for its Storm Shadow capability, with London announcing additional deliveries to replenish Ukrainian stocks and sustain its long-range strike capacity. This is in addition to French authorisation to manufacture the French variant, SCALP/Storm-Shadow, under licence, while France has also opted to extend the life of its combat-proven SCALP through the Mk2 upgrade as it waits for STRATUS. From this perspective, the UK’s decision runs counter to the commitments made by Paris and London in July 2025, when both countries announced the restart of Storm Shadow production, fifteen years after the last order, as part of what both governments described as a new “Industrial Entente”.
Whether the UK pursues a similar bridging solution remains to be seen, but the debate illustrates a broader challenge facing the Defence Investment Plan: sustaining credible long-range strike capabilities until the next generation of systems becomes operational. For now, many see it as little more than “sticking plasters”, as Tom Sharpe, the retired Royal Navy commander. Or, to put it more precisely, it is simply “cost cutting by another name”, he added…
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