Starmer’s Departure leaves few answers for the future of British defence

With June approaching its end, so has the tenure of the 7th British Prime Minister of the last decade. Sir Keir Starmer’s resignation closes a chapter of strong attempts to reposition the UK as an international player, while failing to show a willingness to adapt to a rapidly changing defence environment. With a change of leadership seeming set towards the former Manchester Mayor Andy Burnham, little has emerged on what to expect for the concerning state of British foreign policy and defence strategy.

For the criticisms of his domestic policy, Keir Starmer has had some limited success on the international stage. Under Starmer’s leadership, the UK has continued its steadfast support of Ukraine, particularly during heated criticism of Kyiv from Washington. Starmer’s strong early relationship with US President Donald Trump was crucial in convincing Washington to maintain its support, even if in a more transactional form. On the other side of the Atlantic, Starmer has also positioned himself alongside key EU partners on defence and economic matters, joining France in a ‘coalition of the willing’, reaffirming Ukraine’s sovereignty.

However, Starmer’s two years in Downing Street have also had significant foreign policy failings. Most critically has been the collapse of his relationship with President Trump following the 2026 US-Israeli war with Iran, which saw the UK refuse access to British bases in Diego Garcia and England for strike missions. Trump’s response of unfavourably contrasting Starmer with his vision of Churchill succinctly reflects the sudden decline in his relationship with the US President.

But perhaps more significant are the questions that Starmer is leaving surrounding defence policy. The much-awaited Defence Investment Plan has yet to be published, while minimal spending rises expected in the plan have caused the resignation of two of Starmer’s most respected ministers, John Healey and Al Carns. The leaked figures have suggested that funding reallocated to defence falls significantly short of what military figures and ministers alike have insisted is required to enable the UK to meet the challenges of the late 2020s.

The failure to publish the investment plan, and rumours of continued underinvestment a year after the 2025 Strategic Defence Review suggests a failure to engage with the demands for hard power that underpin parts of a successful foreign policy. Domestic policy battles over benefits have drawn criticism given the state of Britain’s finances, which has been redoubled since revelations emerged over the apparent underfunding of defence. Starmer enters the twilight of his time at the helm of British politics with continued questions around the future of the country’s diplomatic and military strategy.

Looking forward, the ascension of Andy Burnham, former Mayor of Manchester, to Downing Street seems almost certain given that his expected rival, Wes Streeting, has declined to challenge Starmer, placing his support behind Burnham. With domestic issues being central to Burnham’s campaign, there is unlikely to be a shift in British diplomatic posture away from its current trajectory. Burnham is highly unlikely to decrease his support for Ukraine and might find ways to build on this deep relationship, especially if he can select visionary and empowered foreign and defence secretaries. Similarly, the trend to closer relations with the EU may also continue, while Burnham might look to build a better relationship with the United States given Starmer’s departure.

But while foreign policy might be expected to proceed in the current direction, this might concerningly also happen with defence. If Starmer refuses to address the prolonged issue of the Defence Investment Plan, then Burnham will have to deal with it immediately, or otherwise attempt to kick it into the long grass. Burnham has won significant support in the left of the Labour Party and will face pressure to increase spending on social programmes, benefits, health and education among others, adding to pressure from the treasury to limit spending increases on other areas, most critically defence. On the other hand, Burnham has been shown to be engaging with the challenge, proposing special bonds to fund investment, though this may not pass through the already suspicious bond markets. There are many options available to Burnham, and as many inside his own party joke, few know where his political stance truly lies.

As the Starmer Premiership transitions into one led by Andy Burnham, the UK’s defence policy remains at an inflection point, with investment undecided and far below what key policymakers deem necessary for evolution into the 2030s. While Starmer has made admirable attempts to secure the UK against trans-Atlantic division as well as strengthen the position of Ukraine, he has failed to demonstrate to the British public and his own MPs the urgent need to invest and redefine British defence strategy and international position. While his apparent successor is energetic to address the challenge, it is yet to be seen how the demands of protecting the UK can occur without significant sacrifices, and whether Burnham can make these choices while protecting the vulnerable British economy.

By Archie Mackesy - Operations Associate, St James’ Foreign Policy Group