British Defence Secretary John Healey resigned on Thursday, accusing Prime Minister Keir Starmer and the Treasury of failing to commit sufficient resources to protect the country at a time of rising global threats. In a resignation letter posted to his X account, Healey wrote that Starmer had been "unable, and the Treasury unwilling" to fund the nation's defence needs, warning that the proposed settlement would make Britain "less safe". The departure is one of the most significant cabinet resignations of Starmer's tenure and lands at a deeply difficult political moment for the Labour leader.

At the centre of the dispute is the long-delayed Defence Investment Plan (DIP), a document outlining defence funding for the coming decade that Starmer has promised to publish before a NATO summit in Ankara on 7 July. Healey said he was shown the full plan for the first time on Monday and found it deeply inadequate. Under its terms, defence spending would rise to only 2.68% of GDP by 2030 — well below the 3% target Starmer had pledged to reach, and with no firm date attached to that commitment. Starmer had previously promised NATO allies, including US President Donald Trump, that the UK would eventually reach 3.5% of GDP by 2035. Yet sources close to Healey say the Treasury was only willing to find £13.5bn of a £18bn funding gap, offering an extra £2bn — roughly 0.08% of GDP — by 2030. Healey described this as falling "well short of what is required for defence and the country at this dangerous time".

The resignation exposed a range of pressing strategic complications. The UK is a participant in AUKUS, a nuclear-powered submarine programme with Australia and the United States, and a one-third partner alongside Italy in the GCAP next-generation fighter jet programme with Japan — whose prime minister is due to visit London on Sunday. A planned joint media event at Portsmouth naval base with Australia's deputy prime minister to discuss AUKUS progress was abruptly cancelled after Healey's resignation became public, sending an awkward signal to a key ally already questioning Britain's ability to deliver on its commitments. Former Australian foreign minister Gareth Evans had told an independent inquiry just hours earlier that meeting project timelines required "heroic levels of optimism".

The funding crisis has deep roots. Britain's Ministry of Defence has not produced a properly costed equipment plan since 2022, when costs already exceeded the budget by £16.9bn. That gap widened to £28bn following a defence review published last year. The geopolitical environment — Russian aggression in Ukraine, tensions in the Strait of Hormuz, and sustained pressure from Washington to reduce European dependence on American security guarantees — has only sharpened the urgency. Healey's complaint, shared by defence analysts, is that Starmer sat on the problem for months before making what the former secretary viewed as an insufficient offer.

The political fallout extends beyond defence policy. Several cabinet members have left the government in recent weeks, but none held as prominent a role as Healey. A by-election in the Makerfield constituency next Thursday, where Greater Manchester mayor Andy Burnham — widely seen as a potential leadership challenger — is standing for a parliamentary seat, adds further pressure on Starmer. The chair of parliament's defence committee called the resignation "a grave moment", while analysts warned it "underlines that Starmer has become a lame duck prime minister who cannot get decisions through his own government". Starmer responded to Healey's letter saying his spending plans would allow the armed forces to "transform and modernise", but faces the immediate challenge of appointing a new defence secretary and salvaging a credible funding plan ahead of the NATO summit.