The United Kingdom published its long-delayed Defence Investment Plan on Tuesday — nine months behind the original schedule — timed to land just before the NATO leaders summit in Turkey on 7 July. The plan commits £5 billion for drone and autonomous weapons investment, £15 billion for the Trident nuclear warhead programme, at least six new hybrid naval vessels, and a target of raising defence spending to 3.5% of GDP by 2035. The Ministry of Defence had requested £28 billion in additional funding; Treasury and No. 10 agreed to £13.5 billion. The gap — roughly £14.5 billion — is not a rounding error. It is the reason two defence ministers resigned in the weeks before publication: Defence Secretary John Healey said the draft plan fell “well short” of what was needed; Armed Forces Minister Al Carns said it was not “transformative enough.” The plan’s actual publication, under replacement Defence Secretary Dan Jarvis, came after Jarvis spent two weeks “refocusing” it on lessons from Ukraine and the Iran conflict. Former Chief of the Defence Staff Admiral Sir Tony Radakin, meanwhile, warned on Sunday that any incoming prime minister would need to pass a “Moscow test” — asking how Britain looks to Russia — as much as the domestic political tests Burnham has been setting himself.
The received wisdom
The case for the DIP’s ambition is not hard to make. Ukraine has demonstrated that industrial-scale drone warfare, long-range precision strike, and electronic warfare capabilities have transformed the character of conventional conflict in ways that legacy force structures are not designed to meet. The UK’s armed forces have been shrinking for thirty years; the army has fallen to 73,000 and will grow only modestly to 76,000 under this plan. At least six admirals and generals have publicly stated in the last year that current capabilities are inadequate for the threat environment. Defence Secretary Jarvis’ framing — that “uncrewed systems are defining conflicts” and that this is “the largest ever UK investment into these evolving technologies” — reflects a genuine shift in doctrine, even if the funding falls short of what the military asked for.
The NATO-summit timing also matters politically. Britain positioning itself as the alliance’s most serious European contributor — this plan is described as the UK’s biggest NATO commitment since the alliance’s founding — has real diplomatic value at a moment when European defence spending is under intense scrutiny from Washington.
A different read
The plan’s political packaging obscures a fundamental fiscal problem that its proponents are reluctant to state directly. The UK is committing to 3.5% of GDP on defence by 2035. In 2026, UK GDP is roughly £2.7 trillion; 3.5% would imply an annual defence budget of approximately £95 billion, compared to roughly £55-60 billion today. That is a near-doubling of defence spending in nine years. At the same time, the government is managing a welfare and public services cost base that is already absorbing record levels of NHS spending, benefits uprating, and debt interest payments that consume a third of tax revenues. Andy Burnham has said he would fund defence by reducing the welfare bill through employment — a position that is either a serious structural reform agenda or a political formula that dissolves on contact with the actual welfare caseload. We do not yet know which.
The deeper issue that Admiral Radakin’s “Moscow test” framing exposes is that British defence policy has for thirty years been conducted as a series of rounding errors — small cuts in manpower, capability, and readiness that seemed individually manageable but have produced, cumulatively, what the Admiral described as capabilities that are “too bare,” affecting ships, aircraft, tanks and armoured vehicles simultaneously. The DIP addresses some of this — the drone investment is real, the AUKUS submarine partnership gives the Royal Navy a long-term pathway — but it does so at a pace determined by what the Treasury would accept rather than what the strategic environment demands.
There is a conservative case for taking the military’s requests seriously that is neither jingoistic nor reflexively hawkish. It begins from the observation that defence is the one public good that cannot be quickly scaled up in response to events. A hospital built in five years can treat patients in year six. A submarine fleet requires a decade to commission, train crews for, and deploy effectively. The investment decisions made now — or deferred — determine Britain’s actual military capacity in 2035 and beyond. The Treasury’s preference for limiting commitments is understandable from a fiscal management standpoint; it is myopic from a strategic one.
The Conservative opposition’s description of the plan as “too little, too late” is superficially correct but conveniently ignores that the decimation of UK defence capability was well advanced on their own watch through the 2010s and early 2020s. The Lib Dems’ claim that Britain has been “dangerously short-changed” is accurate but offers no funding alternative. What the DIP reveals, ultimately, is that British politics across all parties has never had a serious public conversation about what security costs, what threats are real, and what taxes or spending trade-offs it would accept to fund a credible deterrent. Burnham is now about to inherit that conversation, which is harder than inheriting a plan.
What to watch
The NATO summit on 7 July is the first external validation test. Whether allied leaders treat the DIP as a serious contribution or a marginal one will signal how much diplomatic credit the UK can draw on in the months ahead.
Burnham’s specific position on the 3.5% GDP target deserves scrutiny. He has endorsed the DIP broadly, but endorsing a document is not the same as identifying the fiscal mechanism for its implementation. The Chancellor’s spending review in autumn 2026 is when the numbers will or will not add up.
The two ministerial resignations over the plan’s inadequacy set a political precedent. If the strategic environment deteriorates — a renewed Russian offensive, further Hormuz instability, an event that makes current UK capabilities visibly inadequate — the political cost of the Treasury’s parsimony becomes very high very quickly. Watch whether Jarvis, having “refreshed” the plan, finds himself in the same position as Healey within eighteen months.
— J