A treaty that would transfer sovereignty of the Chagos Islands to Mauritius has become "impossible to agree at political level", and the related bill will not finish its passage through Parliament, Foreign Office minister Stephen Doughty told the Commons. Doughty said the deal was originally negotiated in close coordination with the United States, but former President Donald Trump's stance appears to have shifted, prompting Washington to withdraw its support.
Under the proposed agreement, the United Kingdom would hand over the Chagos archipelago to Mauritius while leasing Diego Garcia – the site of a joint UK‑US military base – for 99 years to preserve defence operations. Trump had previously described the treaty as "very strong and powerful" and noted that it had been "tested thoroughly at all levels of the United States system under two administrations and found to be robust". With the US backing gone, Doughty explained that updating the 1966 UK‑US "exchange of notes" on defence use of the British Indian Ocean territories is now unfeasible, a step required to ratify the treaty.
Because the bill cannot be carried over to the next session due to its advanced stage, it will lapse this parliamentary term. Nevertheless, Doughty said the government remains confident that the Diego Garcia treaty remains the best way to safeguard the base's operation for future generations and allies. He acknowledged that the delay will be "sad news to many Chagossians – although I accept not all – who rightly see it as the only viable means to a sustainable programme of resettlement, which Mauritius would be able to implement under its terms." The next steps hinge on whether diplomatic negotiations can revive US support or produce an alternative arrangement.
The most striking element of the episode is how a treaty once lauded by the United States as "very strong and powerful" collapsed after a single change in American leadership, underscoring the fragility of agreements that depend on personal political calculus rather than institutional commitment. Stephen Doughty's admission that the treaty is now politically impossible highlights the outsized influence of the Trump administration's shift on a long‑standing defence partnership.
This setback fits into a broader pattern of strain in the trans‑Atlantic alliance, where divergent views on issues such as the Iran conflict have begun to surface publicly. The difficulty in updating the 1966 "exchange of notes" reflects how historic defence pacts are being re‑examined in an era of changing geopolitical priorities, especially as the UK seeks to redefine its post‑Brexit security posture.
For Africa, the stalled handover to Mauritius delays a potential reshaping of control over a strategic point in the Indian Ocean. If Mauritius eventually assumes sovereignty, it could alter regional security dynamics and influence maritime traffic that is vital to Nigerian oil exports. The episode also signals to other developing nations that reliance on great‑power guarantees can be precarious.
Watch for any renewed diplomatic overtures from Washington or a revised UK proposal that might revive the treaty in a future parliamentary session, as the fate of Diego Garcia remains a barometer of UK‑US defence cooperation.
