Outgoing British Prime Minister Keir Starmer on Tuesday presented his government’s long-delayed Defence Investment Plan, committing an additional £15 billion over four years and bringing total defence spending to nearly £300 billion by 2029. The blueprint, which Starmer described as his legacy and a platform for his successor, will be taken to the NATO summit in Ankara on 7–8 July. It marks a doctrinal shift away from large crewed platforms: £5 billion is earmarked for drones and autonomous systems, the Royal Navy is to become a “hybrid” force built around six new common combat vessels rather than a planned class of destroyers, and the army and air force will integrate uncrewed systems and artificial intelligence. The announcement follows the resignation of defence secretary John Healey, who quit earlier this month arguing the settlement was too small to keep Britain safe.

The plan drew a mixed reception. NATO Secretary General Mark Rutte welcomed it as a step towards the alliance’s spending goals, while the GMB trade union said it offered stability for a sector beset by insecurity. In London, however, opposition Conservatives and Liberal Democrats condemned the package as too little and too late. Former Joint Forces Command chief General Richard Barrons told the BBC that the uplift still left a funding gap and that “more has to be done sooner.” Military chiefs had identified a £28 billion shortfall over four years; the £15 billion addition, together with a requirement for the Ministry of Defence to find £11 billion in internal efficiencies, leaves the force structure under strain, according to defence analysts.

The additional spending will be financed by cancelling or deferring road and energy infrastructure projects, not through new borrowing, Chancellor Rachel Reeves confirmed. The plan raises defence spending to 2.7 per cent of GDP by 2029, with a trajectory to 3 per cent in the next parliament, and keeps the UK on course for the NATO-agreed target of 3.5 per cent by 2035. When wider security-related expenditure is included, the government says the total reaches 4.2 per cent of GDP, still short of the 5 per cent benchmark urged by Washington. The emphasis on cheap, attritable drones and AI-enabled targeting draws directly on lessons from the war in Ukraine and the recent Iran-linked exchanges in the Middle East, where high volumes of low-cost systems have altered the character of conflict.

Starmer’s imminent departure — he is expected to hand over to Labour leadership frontrunner Andy Burnham by late July — injects uncertainty into the plan’s implementation. Burnham has signalled support for defence investment, but the document can be revised by a new government. Viewed from European capitals, the British move is part of a broader rearmament trend driven by the perceived Russian threat and US demands for greater European burden-sharing. The dossier now moves to Ankara, where NATO leaders will discuss collective spending commitments and the alliance’s military posture.