The UK is unique among major powers for being dependent on another nation for the long-term viability of its nuclear forces. Even though the use of the deterrent remains under the sole control of its own politicians and naval officers, because we use shared missile and reactor technology with the US, the UK ultimately relies on America for equipment and know-how.
This is one of the facts of our current nuclear position – a political reality that is neither perfect nor pretty. It is something Andy Burnham will have to wrestle with if he is as serious as he claims to be about rearmament. The most glaring issue is the question of budget. So far, the Burnham administration has enjoyed a summer fortnight of handing out relatively small amounts of money. The nuclear question is far more existential, involving choice and sacrifice not only about budgets, but also about what sort of power Britain wants to be.
Staying in the nuclear game today takes up a huge chunk of the UK’s defence budget. According to the Ministry of Defence’s recent Defence Investment Plan, maintaining Britain’s nuclear forces will consume between 20 and 25 per cent of the department’s funds over the coming years. Over a similar period, the US will spend about 8 per cent of its defence budget on its nuclear weapons, and the French 13 per cent. Should Burnham choose to maintain Britain’s nuclear deterrent – as he has said he will – the level of investment required will demand not simply a difficult Budget or two, but a national effort on a scale we have not seen since the Cold War.
John Healey, who resigned as defence secretary over the lack of defence investment under Keir Starmer, is now, as Chancellor, faced with the unenviable task of rustling up the cash. Healey well understands why the UK’s nuclear programme is consuming so much of our defence resources. For the best part of three decades, as the focus of defence turned first to the dividends of peace after the Cold War, and then the messy battles of counterterrorism and counter-insurgency, Britain’s nuclear programme was deprioritised. The basic infrastructure and skills of our nuclear weapons facilities, our submarine manufacturing and our maintenance shipyards were left to decay, to the point that bringing them back to life will come at extraordinary cost.
Strong leadership is needed if the UK is to restore its nuclear programme. The truth is we are now playing a challenging game of catch-up that will demand a long, slow grind of long-term investment, the fruits of which will not be seen for years. Without this investment, the years of neglect cannot be undone.
In the short term, Britain will not be able to unpick its nuclear relationship with the US. The process of pursuing a more sovereign deterrent would come at even greater cost than the one we face today. Yet that is not the end of the story. A year ago, without much fanfare, Starmer and Emmanuel Macron signed the Northwood Declaration, reaffirming their countries’ “commitment to nuclear cooperation”. In the context of Donald Trump’s wavering interest in European security, the two established European nuclear powers committing to greater coordination is significant. Collaboration with our French counterparts might become as important over time as those instincts that have previously been drawn to the huge resources of the US. Britain’s nuclear ambitions could, in other words, presage a new era of European cooperation.
Unlike the UK, France maintained much of its investment in its nuclear programme in the early 21st century. It kept up both its submarine-launched nuclear weapons and air-launched systems, and appears to have done so with less impact on the country’s defence budget. There may well be precious lessons for the UK here. At the very least, the consistent focus on nuclear from the very top of the French political system seems to have ensured that their programmes have not suffered in the same way that Britain’s have: France kept greater sovereign control of its nuclear deterrent – and at a lower cost.
For as long as the UK maintains its aspiration to be the leading European nuclear power in Nato, a big slice of the defence pie will be eaten up by its nuclear forces. Herein lies Burnham and Healey’s challenge. To conserve Britain’s position, this government will need to dig deeper into the nation’s resources than any other in the past 30 years – not just to hit the spending target of 3 per cent of GDP on defence being discussed, but also the 3.5 per cent set as the Nato goal for 2035.
Put those numbers into perspective. In 2024-25 the UK spent just over £60bn on defence. Had we spent 3.5 per cent of our national budget on defence that year, expenditure would have reached something like £110bn. That additional £50bn is equivalent to more than the annual budget of the Home Office – policing, borders, courts and prisons combined.
Hitting our defence spending goals is not the stuff of marginal tinkering. The government’s task – should it pursue its stated goals in this area – will amount to a fundamental reordering of national spending. This will be a hard sell. Given the state of many family finances in the country, it is going to be a monumental task to convince the public it’s necessary to make up for decades of past investment failures without it feeling like fresh austerity.
Simon Case was the UK cabinet secretary from 2020 to 2024
[Further reading: The new nuclear terror]
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This article appears in the 29 Jul 2026 issue of the New Statesman, The new terror
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The House of Commons Library Research Briefing in August 2025 “The cost of the UK’s strategic nuclear deterrent” available online as a pdf file at https://researchbriefings.files.parliament.uk/documents/CBP-8166/CBP-8166.pdf provides a good summary of the capital and revenue costs of maintaining our nuclear deterrent.