The "Special Relationship" is facing its first major stress test of the new era. US President Donald Trump has launched a blistering public attack on the UK government’s plan to hand over sovereignty of the Chagos Islands to Mauritius, explicitly demanding: "DO NOT GIVE AWAY DIEGO GARCIA!"

In a characteristic late-night salvo on his Truth Social platform, Trump bypassed diplomatic channels to deliver a direct warning to Prime Minister Keir Starmer. He labeled the agreement—which includes a 99-year leaseback of the strategic Diego Garcia military base—as a "big mistake" and a sign of weakness. His intervention throws a grenade into a delicate geopolitical negotiation, aligning him with critics who argue that leasing a base from a Chinese-aligned Mauritius is a strategic suicide note.

Strategic Vitality in a Volatile Region

Trump’s rhetoric was not just bluster; it was grounded in hard-nosed security concerns. He explicitly linked the Chagos issue to the escalating tensions with Iran, warning that the Diego Garcia base might be needed to "eradicate a potential attack by a highly unstable and dangerous Regime." The base, a remote atoll in the Indian Ocean, is a lynchpin of Western power projection, supporting long-range bomber operations and submarine logistics that are critical for checking adversaries in the Middle East and the Indo-Pacific.

"Leases are no good when it comes to Countries," Trump wrote, casting doubt on the reliability of the 99-year guarantee that London and Washington have touted as the deal's safeguard. His comments suggest a fundamental distrust of international legal agreements when hard sovereignty is at stake, a worldview that clashes directly with the Foreign Office’s rules-based approach.

• The UK Response: Downing Street is scrambling to contain the fallout. A Foreign Office spokesperson reiterated that the deal is "crucial to national security" and the only way to legally secure the base’s future. However, having the US President publicly undermine the agreement emboldens opposition figures like Nigel Farage, who praised Trump’s intervention.
• The China Factor: Looming behind the headlines is the shadow of Beijing. Critics fear that Mauritius, which has deepened economic ties with China, could eventually allow Chinese surveillance assets into the archipelago, rendering Diego Garcia operationally compromised.

A Diplomatic Headache

For Keir Starmer, this is a nightmare scenario. He is caught between a binding international legal obligation to decolonize and the unpredictable demands of his most important ally. Trump has effectively weaponized the Chagos issue, turning a complex diplomatic settlement into a litmus test of loyalty to the US.

As the clock ticks down on the handover, the question is no longer just about sovereignty; it is about whether the UK can chart an independent foreign policy while the elephant in the room is shouting orders. Trump has drawn a red line in the Indian Ocean, and he dares Starmer to cross it.