In his speech to this year’s Munich Security Conference Prime Minister Keir Starmer emphasized the security challenges facing Britain and its European partners, including the need to rearm: Britain and Europe ‘must spend more, deliver more and coordinate more,’ he said.
Yet only when the British government publishes its long-promised Defence Investment Plan will we discover what this means: more indecision or effective action on how Britain will pay for its rapidly changing defence needs.
The government has taken nearly two years to get to this point. Starmer announced a new Strategic Defence Review (SDR) shortly after assuming office in July 2024. Published after some delay the following June before a NATO summit in the Netherlands, the SDR accepted all 62 recommendations of its three external advisers and, by the end of the Hague summit, Starmer committed the UK to the new NATO target of defence spending of 3.5 per cent of GDP plus an additional 1.5 per cent spent on wider defence infrastructure by 2035.
The Russia threat
Like its immediate predecessors, the 2021 Integrated Review and the 2023 Integrated Review Refresh, the 2025 SDR continued to identify Russia as a short-term threat to the UK and its NATO partners along with China, North Korea and Iran in the longer term. This was uncontroversial with the only debate being about when NATO forces needed to be in a position to deter and, if necessary, defeat any Russian foray into the territory of a NATO member.
Here the SDR abandoned the policy of its predecessors which had promised to deliver armed forces in a decade. Instead, reflecting the assumptions of NATO planners, it emphasized the immediacy of the threat posed by Russia and the need for the armed forces of the UK and its allies to be ready. Few commentators disagreed.
The other big difference between the situation at the start and end of the SDR process revolved around the commitment of the United States to NATO. Donald Trump’s re-election as US president, the apparent closeness of members of his administration to Russia and uncertainty about Trump’s commitment have raised significant questions about the US adherence to Article 5 and about Europe’s dependency on the US.
On this, officials remain divided. The optimists argue that the Trump presidency is a blip and that the US commitment to European security would be restored with the next president in January 2029. All that Europe and Britain need do is ride out the next three years. In contrast, the pessimists declared that the US commitment to NATO has effectively ended. This leaves Britain particularly vulnerable because of the past 80 years of UK–US defence integration.
NATO first
While most commentators generally agree with the SDR’s ‘NATO First’ focus and with its 62 recommendations, questions remain: How are these recommendations going to be funded? And how does the continued language of Britain being Europe’s leading military power stand up when Germany is committed to much higher levels of defence spending?
In part, the SDR team sought to reconcile the ambitions of their review with likely funding through two measures. First, they largely adopted the optimists’ perspective and, while they spoke of a greater contribution from Europe – including Britain – they did not, at least in public, question the US commitment to Europe. Second, they adopted a standard defence-review tactic of assuming efficiency savings, this time through the use of artificial intelligence allowing civil servant numbers to be further reduced. On the question of Britain’s position as Europe’s leading military power the SDR and government merely reiterated the narrative of British pre-eminence.
So much for Britain’s ambitions for its defence capabilities. What followed, however, was prevarication.
The government promised to release a Defence Investment Plan in autumn 2025 that would demonstrate the affordability of the strategy. Throughout autumn and into the new year rumours circulated about a sizeable gap between the estimated cost of delivering the defence programme and the funding promised in the government’s broader Spending Review, published in spring 2025.
This was hardly a surprise. Even before the SDR the National Audit Office’s audit of the most recent annual Ministry of Defence Equipment plan identified a deficit of nearly £17 billion. Implementing all 62 recommendations of the SDR simply exacerbated the problem even if the estimated £6 billion of efficiency savings could be achieved. The timeline for the publication of the Defence Investment Plan was subsequently changed to pre-Christmas and then the new year.
As yet, there is no sign of it, but indications are the government hopes to publish the plan before Easter. In the meantime, rumours about potential measures, including a reduction from two to one army divisions, the cancellation of the £6.2 billion Ajax armoured vehicle and a reduction in the Navy’s Type 26 frigate programme as ships currently under construction are allocated to Norway instead.
New targets
Nevertheless, at Munich in February, Starmer reiterated Britain’s commitment to be at forefront of European security. So, what is the way forward? The government has four options.
The first is to follow the German example and significantly raise defence spending to nearer NATO’s new target of 3.5 per cent in this parliamentary cycle through a combination of increased taxation and/or borrowing. This is the preferred option of many defence commentators but would represent a risky change of tack. It comes at a time of high government debt and competing demands for public investment in areas ranging from health and education to infrastructure and wider resilience.
The second option is to abandon Britain’s commitment to a nuclear capability and instead spend all the earmarked defence budget on conventional forces. For some in defence this has appeal, but the political consequences would be seismic. NATO’s nuclear guarantee would come into question given that only Britain and the US provide the requisite nuclear forces.
The third option is to cede the mantle of being Europe’s leading military power, run down Britain’s conventional forces and free-ride off European states that are geographically closer to Russia. In such a scenario, Britain would become the equivalent of a nuclear-armed Belgium. This would represent a turning point for Britain and a difficult one for a government to sell to the electorate and its allies.