Why the UK Is Reviewing the Chagos Islands Agreement

The United Kingdom is reassessing an agreement that would transfer sovereignty over the Chagos Islands to Mauritius, after the United States signalled that it does not support the deal in its current form.

What changed

Defence Secretary Wes Streeting said the agreement must be reviewed because Washington does not support the draft. The review follows criticism from US President Donald Trump and is intended to find an arrangement that protects the long-term future of the joint UK-US military base on Diego Garcia.

The review is not expected to follow a fixed timetable. Government sources say the central requirement remains American backing, while officials work with the UK, US and Mauritius to revise the arrangement.

Why Diego Garcia matters

Diego Garcia is the largest island in the Chagos archipelago and hosts a strategically important military facility. Under the earlier proposal, Mauritius would receive sovereignty while the UK would lease the base back for 99 years. The proposed lease was reported at an average cost of £101m per year.

The islands have been disputed for decades. Mauritius argues that it was compelled to give them up in 1965 as part of the process leading to independence. In 2019, the International Court of Justice issued a non-binding advisory opinion saying the UK should end its administration of the territory as rapidly as possible.

What happens next

The immediate focus is on finding a version of the agreement that secures the base and can win support from all the parties. Streeting said no money would be handed to Mauritius at this stage while the review continues.

The outcome could affect UK-Mauritius relations, the future of the military base and the wider security balance in the Indian Ocean. The BBC report used for this summary was published on 23 September 2026.

Source

This article is an original summary based on reporting by BBC News: UK to review Chagos Islands deal over lack of US support.