London: Britain formally signed an agreement on Thursday handing over sovereignty of the contested Chagos Islands to Mauritius, a move aimed at preserving the future of a critical US-UK military base on Diego Garcia, the largest island in the archipelago.
The deal underscores the strategic importance of the base for British national security while addressing a decades-long colonial dispute. Under the terms, the UK will pay Mauritius £101 million ($136 million) annually to lease back Diego Garcia for at least 99 years.
British Prime Minister Sir Keir Starmer emphasized the base’s role in counterterrorism and intelligence, calling it right at the foundation of our safety and security at home. The agreement was signed virtually by Starmer and Mauritian Prime Minister Navin Ramgoolam after a brief legal hurdle delayed the process.
Earlier on Thursday, a UK High Court judge issued an injunction temporarily blocking the transfer, responding to a legal challenge from two Chagossian women-Bernadette Dugasse and Bertrice Pompe, who represent the island’s displaced original residents.
I’ve signed a deal to secure the joint UK-US base on Diego Garcia.
This base is vital for the safety and security of the British people and today’s agreement is the only way to protect our country for many years to come.
I will always act in our country’s national interest. pic.twitter.com/13YWwEPrvg
— Keir Starmer (@Keir_Starmer) May 22, 2025
Evicted in the 1960s and 1970s to make way for the US military base, the Chagossians have long sought the right to return. The injunction was later lifted by another judge, Martin Chamberlain, who ruled that further delay would cause substantial prejudice to UK interests.
The Chagos Islands, located in the Indian Ocean, were separated from Mauritius by Britain in 1965, three years before Mauritius gained independence.
This controversial move allowed Britain to lease Diego Garcia to the United States for military purposes, facilitating strategic operations from Vietnam to Afghanistan.
Mauritius has long contested Britain’s sovereignty over the islands. In recent years, the United Nations and the International Court of Justice (ICJ) have called for the UK to return the territory to Mauritius. The ICJ’s 2019 advisory opinion described Britain’s separation of the islands as unlawful.
The UK government, however, argues that the military base’s presence is vital to national security and that returning the islands without securing the base’s future would be untenable.
Negotiations on the handover began in 2022 under the previous Conservative government and continued after Starmer’s Labour Party took office. The deal faced criticism from opposition Conservatives, with leader Kemi Badenoch calling it an act of national self-harm and objecting to paying to surrender British territory.
Alongside the sovereignty transfer, the agreement includes a trust fund to support the displaced Chagossian community, though details about resettlement plans remain vague. Mauritius retains control of the islands but cannot resettle Diego Garcia, preserving its strategic military function.
