A dramatic reversal by former US President Donald Trump on a critical defence deal has thrown Sir Keir Starmer's premiership into a fresh diplomatic crisis and severely undermined his carefully cultivated role as a key ally to the American leader.
From Oval Office Endorsement to Public Rebuke
In a stunning political U-turn, Donald Trump has denounced the UK's plan to hand over the Chagos Islands, including the strategically vital Diego Garcia airbase, to Mauritius. He labelled the deal an "act of great stupidity," a statement that will have sent shockwaves through Downing Street on Tuesday, 20 January 2026.
This condemnation marks a complete reversal from his position less than a year prior. In February 2025, during Sir Keir Starmer's first Oval Office meeting with Trump, the US president was publicly supportive. When questioned by reporters, Trump stated, "I have a feeling it is going to work out very well. I think we will be inclined to go along with your country."
This endorsement, later formally backed by Secretary of State Marco Rubio in May 2025, was pivotal. It gave the Labour government the necessary American blessing to proceed with the controversial handover, despite lobbying against it by figures like Nigel Farage and a warning from then-Foreign Secretary David Lammy that US opposition would scupper the plan.
The Greenland Grievance: The Real Reason for the Reversal?
So what prompted Trump's spectacular change of heart? While sustained lobbying from the deal's opponents is a factor, the primary catalyst appears to be the escalating row over Greenland.
Political analysts suggest Trump has now drawn a direct, and for the UK government, disastrous parallel. He understands that the same principles of international law used to argue that the Chagos Islands belong to Mauritius could also challenge Denmark's sovereignty over Greenland—a territory he has repeatedly expressed a desire for the US to acquire.
Sir Keir's recent decision to publicly stand with Denmark, a NATO ally, against Trump's threats and tariff demands over Greenland is seen as a key trigger. Trump, known for holding grudges, has interpreted this as a betrayal. His sudden opposition to the Chagos deal is widely viewed as retaliatory, opening a new front in a rapidly deteriorating relationship.
The Fall of the 'Trump Whisperer' and UK Foreign Policy Weakness
The implications for Sir Keir Starmer are profound. He had built a significant part of his foreign policy identity on being the so-called "Trump whisperer"—a leader who could reliably manage and influence the capricious US president. This reputation secured perceived wins, including a favourable trade deal and the initial Chagos agreement.
This latest development shatters that image. If Starmer's unique channel of influence with Trump is closing, it strikes at the heart of his strategic aim to act as the essential bridge between the United States and Europe. Without that role, Britain's global position and diplomatic leverage are significantly weakened.
The prime minister's attempts to placate Trump, including facilitating a historic second state visit by the president to the UK, now seem for naught. Even the prospect of a reciprocal visit by King Charles to the US appears insufficient to temper the current hostility. The Chagos U-turn is more than a policy dispute; it is a stark signal that the special relationship under the Starmer-Trump dynamic is in serious trouble.
