Keir Starmer inherited two wars and a country disconnected from the EU when he arrived in Downing Street – and that was before Donald Trump crash-landed at the White House and undermined the foundations of the UK’s most important alliance.

It was a context that would have tested any prime minister, though in many respects Starmer negotiated it carefully. But longer-term questions of Britain’s security remain unresolved, and the UK’s place in the world is less certain.

“I wouldn’t be the first person to say that Starmer would be a great diplomat,” said Olivia O’Sullivan, a foreign policy expert at Chatham House. “But what we’ve seen is that the US is not prepared to play such a decisive role in European defence and security – and it’s not clear if enough action has been taken in the light of that.”

Though the ageing Joe Biden and Starmer overlapped for six months, it was the relationship with Trump that was dominant. At first, the Labour prime minister appeared to have struck an unlikely rapport with the Republican.

It was helped by Starmer publicly handing over an invitation to Trump from King Charles for a second state visit when he came to the Oval Office in February 2025. “This is unprecedented,” Starmer gushed, and Trump accepted there and then.

The ensuing state visit last September, with Trump kept tactfully out of London, saw the US president mute a disagreement with Starmer over Palestinian statehood – and the two seemed largely in agreement in condemning Russia over Ukraine.

It was a moment of relative harmony. Trump began his presidency dramatically favouring Russia, lambasting Ukraine’s president Volodymyr Zelenskyy in the Oval Office. European leaders were left aghast at the possibility of Kyiv being abandoned.

On his way back from Washington, Zelenskyy was due in London for a European summit. But he was also flown by helicopter to visit the king at Sandringham in Norfolk. The short trip, approved by Starmer following a Ukrainian request, visibly demonstrated British support for Kyiv at a critical moment.

When Zelenskyy visited the Oval Office again, in August, Starmer was one of several European leaders who flew in alongside him. It was just days after Trump had met Russia’s Vladimir Putin in Alaska, and the US president had appeared convinced that Ukraine needed to be told to give up territory to end the war quickly.

Strength in numbers worked: the Russian demand briefly favoured by Trump drifted from the agenda, and has not been revived since. Peace in Ukraine would have to be lasting, fair and just, Starmer said as he headed into the meeting.

Russian intransigence prevented further progress on Ukraine, so Trump moved on to Venezuela and then Iran, at which point the goodwill evaporated. The UK was not informed ahead of the almost certainly illegal US-Israeli attack on Iran in February, which began with the killing of supreme leader Ali Khamenei.

Yet within days, Trump was complaining about an initial refusal by Starmer to allow the use of RAF bases for bombing Iran. “This is not Winston Churchill that we’re dealing with,” Trump said in early March, beginning a month of jibes, as the bombing of Iran continued to a limited purpose for 38 days while oil prices soared.

Starmer refused to rise to the petty bait, avoiding a deeper split with the US – while refusing to join in with the war Trump had started, other than to allow attacks on Iranian missile launch sites from RAF Fairford, Gloucestershire.

“President Trump has expressed his disagreement with our decision not to get involved in the initial strikes, but it is my duty to judge what is in Britain’s national interest,” Starmer told MPs in characteristically wordy fashion.

Sir Peter Westmacott, a former UK ambassador to the US, argued that “foreign policy has been an area of relative strength” for Starmer, and that the prime minister had got off a strong start with Trump, “though the president’s failure to consult with allies or justify his war with Iran left him with little choice but to stand aside”.

Keeping out of the Iran war was also popular with a British public alarmed by Trump’s reckless behaviour, though it did nothing to help Labour’s overall poll ratings. Relations with the US leader were eventually smoothed over by approving the king’s visit to Washington, New York and Virginia in April.

“As a Labour prime minister he would never naturally have been on side with Trump, but he hasn’t let it knock him off key positions on issues like Iran,” said Peter Ricketts, a former UK national security adviser. “Plus, he’s avoided outright rows with Trump – as well as carefully deploying the king.”

Britain approved the building of a large new Chinese embassy, despite a series of spying rows, allowing Starmer to visit Beijing in January. Not much was gained from the trip, beyond an agreement to allow Britons 30 days of visa-free travel, and the obligatory cut on whisky tariffs. Nevertheless, the UK hoped for “a more sophisticated relationship” with Beijing, Starmer said.

Starmer tried to pursue a reset with the EU, describing Britain as “very much a part of Europe” at a Blenheim Palace summit in July 2024. But he had given himself little room for manoeuvre by having decided not to try to reverse any part of Brexit. Labour’s manifesto committed the party to staying out of the single market and customs union, and not to reintroduce freedom of movement.

A few days after Hamas’s deadly attack on Israel in October 2023, Starmer, then in opposition, said in a radio interview that the country “does have that right” to cut off electricity and water to Gaza. Later, a Labour spokesperson said he had meant to say that Israel had a right to self-defence, though the comments lingered all the way to the election, where the party lost a handful of safe inner-city seats.

In government, Starmer’s positions on Israel and Palestine were more an exercise in domestic politics. Labour suspended most, but not all, arms sales to Israel in September 2024 and recognised Palestine as a state a year later, with France, Canada and Australia. The limited measures had no effect on an aggressive Israel determined to prosecute destructive wars against Hamas, Hezbollah and finally Iran.

The paucity of independent British power was demonstrated by the three-week struggle to get a single warship, HMS Dragon, to Cyprus after a Hezbollah drone hit the RAF base at Akrotiri. A 20-year minesweeping Royal Navy mission in the Gulf had been quietly abandoned at the end of 2025, just before it was needed.

It emphasised how far the UK’s armed forces had been run down since the end of the cold war. The problem was nominally recognised by the prime minister, though he struggled to respond to pressure to increase military budgets in a more uncertain world. Starmer had been surprised by Nato’s plan last summer to increase defence spending by £30bn to 3.5% of GDP by 2035; so the UK was one of the last to sign up.

Instead, Starmer would only commit to increase defence spending modestly, by about £5bn to 2.6% of GDP by 2027, taking the money from the UK’s aid budget. “That is not an announcement I am happy to make,” the prime minister said last February, though any talk of restoring aid spending soon disappeared.

Though the prime minister said Britain “needs to go faster” on defence spending in February, it was not accompanied by fresh commitments. A six-month row about future military spending burst into the open earlier this month with the sudden resignation of the once-loyal John Healey as defence secretary, because Starmer had only offered £2bn more to lift defence spending to 2.68% by 2030.

John Foreman, a former UK defence attache to Moscow, said Starmer was “bounced into increasing marginally defence spending but then not funding promises” as well as exhibiting “a habit of talking big but doing little”.

There were repeated virtual or in-person meetings of the “coalition of the willing” postwar stabilisation forces for Ukraine or peacekeeping in Hormuz. In neither case, there was a deployment, though on Hormuz, it is a promise that his successor will immediately inherit.

Though Starmer forged a strong relationship with France’s centrist president Emmanuel Macron – “we have to show that pragmatic politics is the way the results that matter,” Starmer said when his French counterpart visited last July – talks for the UK to join an €150bn (£130bn) EU defence fund failed over the sum Britain would pay to join. France led the objections.

Starmer had tried to rebuild a more positive relationship with the bloc – “slowly but surely building with the EU,” he said at the G7 summit earlier this month, amid talks of a future mobility scheme for young people in the UK and EU.

But though Starmer was clearly pro-European, the ambition was limited. The prime minister insisted that the UK should not “look backwards” to Brexit – and in a final irony, a planned reset summit next month was postponed in the wake of his resignation.

Sophia Gaston, a foreign policy specialist at King’s College London, said it was Starmer who as prime minister “found himself in the hotseat” after “successive governments have run down the nation’s vital defences”. But with the US unreliable and Britain still detached from the EU, the strategic dilemma is greater.

“Modest, incremental improvements simply don’t cut it,” Gaston said.