Sir Keir Starmer is set to publish the UK’s long-delayed Defence Investment Plan (DIP) before the upcoming NATO summit in Ankara on July 7-8, despite opposition from his likely successor, Andy Burnham. The move comes amid growing tensions within the Labour Party as Starmer prepares to step down as prime minister, with Burnham positioned to assume office by mid-July following the leadership contest.

The ten-year DIP, aimed at outlining military spending and capability upgrades, has been a contentious issue in government circles for over a year. It culminated in the resignation of John Healey as defence secretary earlier this month, a protest against what he saw as insufficient funding. Healey called for a clearer commitment to increase defence spending to 3% of GDP by 2030, whereas Starmer’s plan targets 2.68%, a level Healey and some military leaders regard as inadequate for national security needs.

Starmer views the DIP as a cornerstone of his legacy and is determined to finalize it prior to the NATO meeting, marking his last significant international engagement as prime minister. According to senior officials, the plan includes roughly £13.5 to £14 billion in additional funding over four years, which defence chiefs warn may still be insufficient to maintain current operational capabilities and invest in emerging technologies like drones and artificial intelligence. Some military sources suggest certain exercises and reserve commitments might need to be curtailed under the proposed budget.

Andy Burnham, who recently won the Makerfield by-election and announced his leadership bid, has expressed a preference to review the DIP himself rather than accept a plan drafted under Starmer’s administration. While Burnham’s team has refrained from detailed comment, insiders indicate he intends to reassess the investment strategy once in office, potentially revising or overturning the proposal. This stance creates the possibility of a policy clash between the outgoing and incoming prime ministers.

Despite warnings from former Cabinet Secretary Lord Case and parliament’s intelligence and security committee chairman Kevan Jones, who argue that publishing a major defence plan so close to a leadership transition risks it being disregarded or quickly reversed, Downing Street maintains the DIP’s publication is urgent. Cabinet Secretary Dame Antonia Romeo reportedly advised against new spending initiatives during the leadership uncertainty, but agreed the DIP’s release should proceed given the strategic importance.

Burnham and Starmer have held private discussions aimed at smoothing the transition of power, including arrangements for civil service access and briefings. Senior civil servants have been instructed not to entertain new major policy or spending commitments apart from those already in motion, and Burnham’s team is preparing to engage with departmental officials promptly once nominations close on July 16.

Labour cabinet members such as Environment Secretary Emma Reynolds and Education Secretary Bridget Phillipson have voiced support for a seamless leadership handover. Meanwhile, Chancellor Rachel Reeves has expressed confidence that the DIP will deliver more effective funding to address contemporary defence challenges, despite the controversies surrounding its size and scope.

The forthcoming NATO summit poses a critical backdrop, as allied nations face pressure to demonstrate increased defence spending amid growing geopolitical tensions. The UK’s position in NATO’s spending league tables has declined, intensifying scrutiny of its commitment to collective security. Starmer’s publishing of the DIP appears aimed at affirming Britain’s defence priorities ahead of the summit, even as internal party dynamics signal potential revisions under Burnham’s leadership.