Prime Minister Sir Keir Starmer is preparing to attend this week’s NATO summit amid scrutiny over the United Kingdom’s defence spending commitments and its position within the alliance. The summit is seen as a significant opportunity for Starmer to solidify his legacy, but also poses challenges due to criticism from both international allies and domestic observers regarding the scale and pace of the UK’s military investment.

Starmer recently announced a defence spending plan intended to address concerns raised by NATO allies about Britain’s contributions. The government projects that, when accounting for expenditure on energy security and critical infrastructure, defence spending would reach 4.2 percent of GDP—approaching the 5 percent target NATO agreed upon at last year’s summit. However, critics argue the long-term outlook is less optimistic, with planned spending expected to reach only 2.7 percent of GDP by 2030, falling short of the 3 percent benchmark preferred by some allies and below the 3.5 percent goal aimed for 2035. This disparity has prompted questions about the UK’s ability to maintain its status as a leading military power within the alliance.

The defense investment plan (DIP), regarded by some as insufficient, has attracted particular criticism from figures in the United States, including former President Donald Trump, who has repeatedly urged European NATO members to increase their defence budgets. Trump is anticipated to express dissatisfaction with the UK’s approach during the summit, underscoring tensions within the transatlantic relationship. According to experts, the UK risks being regarded as a middling contributor, ranking around 12th among NATO members in terms of defence spending as a share of GDP.

Despite these concerns, the UK continues to be viewed as a key military actor, especially as Russia’s actions in Europe heighten security anxieties. Starmer has publicly acknowledged the possibility of a Russian attack on NATO territory before the end of the decade. The UK’s nuclear deterrent and special relationship with the United States remain central to the alliance’s strategic framework. Recent increases in defence spending aim to reassure allies and maintain Britain’s role amid broader European efforts to strengthen collective security. Notably, Germany is expected to reach 3.7 percent of GDP in defence spending by 2030, and Poland currently spends around 4.8 percent, surpassing the UK’s planned levels.

British officials emphasize that increased military investment will also benefit U.S. defence firms, as significant portions of the budget are slated for procurement of American-made equipment, including 12 Lockheed Martin F-35A fighter jets. This aspect underscores the economic linkages underpinning the transatlantic defence partnership, with British investment supporting over 160,000 American jobs.

Nevertheless, the government’s fiscal constraints have drawn domestic criticism, with opponents accusing Starmer’s administration of underprioritizing defence in favor of other spending areas. Some observers warn that the UK’s defence capabilities may lag behind evolving global threats unless spending commitments are substantially increased and sustained.

As Starmer approaches what could be his final NATO summit as Prime Minister, the ability to reassure both allies and the domestic audience about the UK’s commitment to defence will be closely watched. The responsibility for delivering on these commitments is expected to pass to his potential successor, with significant pressures remaining on Britain’s role within the NATO alliance.