Three senior defence figures have publicly criticised Prime Minister Keir Starmer for what they describe as underfunding the British military, raising doubts about the government’s defence investment strategy amid growing concerns in Parliament. The remarks came during a series of interventions over the Defence Investment Plan (DIP), which proposes an additional £13.5 billion for the Ministry of Defence (MoD) over the next four years.

Former defence secretary John Healey, former armed forces minister Al Carns, and Chief of the Defence Staff Rich Knighton each expressed reservations about the plan’s adequacy and its ability to meet current and future security challenges. Both Healey and Carns resigned from government last week in protest against the DIP’s funding levels, delivering statements to the House of Commons that underscored their disagreements with the direction of defence policy.

Healey said his resignation was taken with “the very greatest regret and reluctance” but defended it as necessary to safeguarding the future of the armed forces and Britain’s international alliances. He criticised the government’s approach as insufficiently ambitious, stating that incremental adjustments would not meet the scale of transformation needed for the military’s modernization. Specifically, he flagged the DIP’s planned rise in defence spending as a share of GDP—from 2.6% to approximately 2.68% by 2030—as inadequate, noting the absence of a timeline to reach the NATO guideline of 3%, let alone the 3.5% target.

Carns echoed Healey’s concerns, arguing that defence planning overly focuses on past conflicts rather than preparing for future threats. He called on Parliament to demand “transformation” and timely delivery of upgraded capabilities "this side of 2030."

In his testimony to Parliament’s Defence Select Committee, Knighton warned that without increased resources, the UK military will need to reduce operational activities in key areas including Europe, Ukraine, and the Middle East. He emphasized the necessity to “dial back” exercises and engagements if funding does not rise beyond what is currently proposed.

The trio’s criticisms have intensified a debate within the Labour Party regarding Starmer’s defence priorities and his reluctance to override Treasury spending limits set by Chancellor Rachel Reeves. These tensions intersect with wider political dynamics, as upcoming contests such as the Makerfield by-election place additional pressure on the prime minister.

Wes Streeting, former health secretary, suggested Starmer should consider stepping down if Labour’s candidate Andy Burnham wins the by-election. Starmer, speaking from the G7 summit in Évian, dismissed calls for his resignation, affirming his intention to remain fully engaged and contest any leadership challenges.

Responding to the criticism of defence spending cuts, Starmer highlighted the increase in defence outlays achieved during his tenure, claiming responsibility for the largest rise since the 1980s. He noted the DIP would further enhance future capabilities, though he did not commit to additional budget expansions. Sources indicate that Starmer has tasked his new defence secretary, Dan Jarvis, with reviewing the DIP within two weeks and proposing any adjustments before the final plan is unveiled ahead of the NATO summit in July.