A trajectory is not a commitment—it's a direction.
In an era when the language of collective defence has grown louder, the United Kingdom has released a Defence Investment Plan that promises more than its numbers can yet confirm. The government of Sir Keir Starmer has committed to raising military spending toward targets agreed with NATO allies, but the plan's own projections plateau at 2.7% of GDP by 2030 — leaving the steeper ascent to 3% and 3.5% to future parliaments and future budgets. It is a story as old as statecraft itself: the distance between a declared ambition and a funded commitment, measured not in words but in years and billions.
- The UK's Defence Investment Plan arrives under pressure, shaped by the resignation of Defence Secretary John Healey, who refused to sign off on a version he considered dangerously inadequate.
- Despite a headline £15 billion increase over four years, only £10.3 billion is confirmed — the remaining £4.7 billion awaits a future Budget, leaving a significant portion of the commitment unanchored.
- A reported £28 billion internal shortfall between military needs and available funding haunts the plan, a figure the Ministry of Defence has neither confirmed nor dispelled.
- Spending is projected to reach 2.7% of GDP by 2027-28 and then flatline through 2030, making the arithmetic path to NATO's 3.5% target by 2035 deeply unclear.
- The government insists Britain is on a 'trajectory' toward its commitments, but the plan provides no year-by-year roadmap beyond 2027-28, leaving allies and analysts to take the destination largely on faith.
The UK government's Defence Investment Plan, released on Tuesday, carries the weight of a promise and the shadow of a resignation. Prime Minister Sir Keir Starmer described the spending increase as a watershed moment, but the figures inside the document tell a more complicated story.
The UK currently spends around 2.4% of GDP on defence under NATO's broader accounting measure. Starmer had previously committed to reaching 2.5% by 2027, then 2.6% once intelligence spending is folded in, with a stated ambition of 3% by the next parliament. At last June's NATO summit in The Hague, the alliance set an even higher bar: 5% of GDP on defence and security by 2035, with 3.5% earmarked for core NATO-qualifying expenditure.
The plan projects spending will reach 2.7% of GDP by 2027-28 — and then hold there through 2030. The £15 billion added over four years sounds substantial, but £4.7 billion of it remains unconfirmed pending the 2026 Budget. The net gain over the original rejected proposal amounts to roughly £600 million by decade's end.
That original plan was rejected by John Healey, who resigned as Defence Secretary on June 11th after arguing the UK needed a firm commitment to 3% by 2030, not a vague ambition deferred to a future parliament. The government subsequently found an additional £1.5 billion over four years — enough to soften the criticism, but not enough to change the underlying trajectory. Healey has since called for a specific target date and a detailed roadmap to 3.5%.
Adding further unease is a reported £28 billion gap between defence funding and existing military commitments over the next four years — a figure attributed to the Chief of the Defence Staff, though never officially confirmed by the Ministry of Defence.
Starmer maintains that Britain is on track and that the 3.5% NATO commitment 'will be met.' But with spending plateauing at 2.7% through 2030 and no year-by-year projections beyond 2027-28, the path to 3.5% by 2035 would require a sharp acceleration that no current budget has yet funded. Future spending reviews may yet fill the gap. For now, the plan reaches partway up the hill and leaves the harder climb to whoever governs next.
The UK government released its long-awaited Defence Investment Plan on Tuesday, and the numbers tell a story of ambition constrained by arithmetic. Prime Minister Sir Keir Starmer called the spending increase a watershed moment for the nation, but the fine print reveals a gap between what was promised and what the plan actually delivers.
The Ministry of Defence's budget for the current year sits at £68.3 billion. When you add in the broader measure that NATO uses—one that includes military pensions and other security spending—the UK spent roughly £70 billion in 2025, or about 2.4% of the country's economic output. Last February, Starmer committed to raising that figure to 2.5% of GDP by 2027, and then to 2.6% once intelligence and security agency spending gets folded into the NATO calculation. He also stated a "clear ambition" to reach 3% by the time the next parliament convenes. At a NATO summit in The Hague last June, the alliance agreed on a more ambitious framework: members would spend 5% of GDP on defence and security by 2035, with 3.5% going specifically to core NATO-qualifying defence.
But here's where the plan falters. The Defence Investment Plan projects that UK spending will reach 2.7% of GDP by 2027-28 and then remain flat through 2030. That's a gain of only about 0.02% of GDP from the original proposal—roughly £600 million in today's money by the end of the decade. The government has added £15 billion to defence spending over four years compared to previous plans, but £10.3 billion of that has been identified now, with the remaining £4.7 billion to be confirmed at the 2026 Budget.
John Healey, who resigned as Defence Secretary on June 11th, had rejected the original Defence Investment Plan precisely because it fell short. He argued the UK should commit to 3% of GDP by 2030, not sometime in the next parliament, and he warned that the country faced rising threats it could not adequately defend against. After his departure, the government found an additional £1.5 billion over four years—a modest adjustment that did not fundamentally alter the trajectory. Healey has since called for a specific target date to reach 3% and a detailed roadmap to NATO's 3.5% goal by 2035.
Starmer insists the plan puts Britain on a "trajectory" toward the 3% ambition and states that the 3.5% NATO commitment "will be met." Yet the mathematics are difficult to square. If spending reaches 2.7% by 2030 and stays there, it is hard to see how the country gets to 3.5% by 2035 without a dramatic acceleration in future years. The Defence Investment Plan does not provide year-by-year estimates beyond 2027-28, leaving the path forward opaque.
The government has also cited a £270 billion figure for defence spending over this parliament, calling it the largest sustained increase since the 1980s. That number represents the total cash budget for the Ministry of Defence through 2028-29. The additional £15 billion announced this week is meant to show responsiveness to the concerns raised by Healey and others, but it amounts to a modest course correction rather than a fundamental reorientation.
There is also the matter of a reported £28 billion shortfall in the defence budget. The figure, first reported by the Times in January, allegedly came from the Chief of the Defence Staff warning the Prime Minister of a gap between available funding and the cost of existing commitments over the next four years. The Ministry of Defence has not officially confirmed this number, and its origins remain unclear. Whether it represents an internal estimate or something else, it underscores the tension between what the military says it needs and what the government is prepared to spend.
Future spending reviews could change the picture. If the government commits additional resources in coming years, the trajectory toward 3% and 3.5% becomes more plausible. For now, though, the Defence Investment Plan offers a path that reaches partway up the hill by 2030 and leaves the steeper climb to later parliaments. Whether that satisfies NATO allies or adequately addresses the security challenges Healey cited remains an open question.
Notable Quotes
The plan lacks a specific target date to reach 3% and a clear roadmap to NATO's 3.5% goal by 2035.— John Healey, former Defence Secretary
The Defence Investment Plan puts the UK on a trajectory to achieve the ambition of spending 3% of GDP in the next parliament.— Prime Minister Sir Keir Starmer
The Hearth Conversation Another angle on the story
Why does it matter whether the UK hits 2.7% or 3% by 2030 rather than later?
Because NATO allies are watching. If you say you're committed to something and then delay it, it signals either that you don't really mean it or that you can't afford it. Either way, it affects how others plan their own defence.
But the Prime Minister says the plan puts the UK on a trajectory toward 3%. Isn't that enough?
A trajectory is not a commitment. It's a direction. If you're at 2.7% in 2030 and you need to be at 3.5% in 2035, you need to know exactly how you get there. The plan doesn't say.
What changed between the original plan and this one?
About £1.5 billion over four years. That's real money, but it's not transformative. It's what you find when you look harder in the couch cushions, not a fundamental reordering of priorities.
Why did John Healey resign over this?
He believed the country faced real threats and that 2.7% by 2030 wasn't enough to meet them. He wanted 3% by 2030, not by some undefined point in the next parliament. He was saying: this is urgent, not someday.
Is there a scenario where the UK actually reaches 3.5% by 2035?
Yes, but only if future spending reviews commit significantly more money. The plan doesn't show how that happens. It's betting on decisions that haven't been made yet.
What does NATO actually expect?
NATO members agreed to spend 5% of GDP on defence and security by 2035, with 3.5% going to core defence. The UK is saying it will meet that. But the current plan only gets to 2.7% by 2030, which leaves a very steep climb in five years.