What is the UK's Chagos Islands deal and why has Trump criticised it?

January 20, 2026

President Donald Trump has strongly criticized a UK agreement to transfer sovereignty of the Chagos Islands to Mauritius, reversing his earlier endorsement of the deal from February 2025. The arrangement, valued at £3. 4 billion, would allow Britain to lease back Diego Garcia island for 99 years to maintain the crucial UK-US military base located there, while Mauritius gains sovereignty over the archipelago.

Who is affected

US President Donald Trump and the US military
UK Prime Minister Sir Keir Starmer and the UK government
Mauritius (Prime Minister Navin Ramgoolam and Attorney General Gavin Glover)
Chagossians (indigenous people forcibly removed in the 1960s, now living in Mauritius, Seychelles, and the UK, particularly Crawley, West Sussex)
UK Conservative leader Kemi Badenoch, Reform leader Nigel Farage, and Liberal Democrat leader Ed Davey
Denmark (indirectly affected due to Trump's Greenland acquisition efforts)

What action is being taken

The UK is leasing Diego Garcia from Mauritius for 99 years at varying annual costs (£165m for the first three years, £120m for years four through thirteen, then inflation-linked payments)
The US is paying the base's running costs
A £40m trust fund is being established to support Chagossians
Trump is using the Chagos deal as justification for his efforts to acquire Greenland from Denmark

Why it matters

This deal addresses a decades-old colonial injustice stemming from Britain's forced separation of the Chagos Islands from Mauritius in 1965 and completes Mauritius's decolonization process. The agreement is strategically significant because Diego Garcia hosts a vital UK-US military base in the heart of the Indian Ocean that has been used for critical operations including missions to Afghanistan and Iraq during the war on terror. Trump's reversal threatens UK-US relations and the deal's implementation, while his inconsistent positions on sovereignty—criticizing the Chagos transfer while simultaneously attempting to acquire Greenland—highlight broader geopolitical tensions. The controversy also exposes vulnerabilities in the UK's "special relationship" with the United States and creates domestic political pressure on Prime Minister Starmer.

What's next

The deal awaits ratification by the UK Parliament before the transfer of sovereignty can proceed. Mauritian Attorney General Gavin Glover has stated that Mauritius expects the treaty to be implemented as soon as possible in accordance with the commitments made.

Read full article from source: BBC