The United Kingdom has agreed to transfer sovereignty of the Chagos Islands to Mauritius, following a High Court ruling that has cleared the way for Prime Minister Keir Starmer to formalise the contentious agreement. This deal brings an end to decades of British administration over the Indian Ocean archipelago – which has been the subject of ongoing legal and diplomatic disputes since the islands were detached from Mauritius in 1965.

Under the agreement, the UK will pay Mauritius an average of £101 million a year to lease back the base for at least 99 years.

Starmer said that the base, operated by US forces, is crucial for British counterterrorism and intelligence and is “right at the foundation of our safety and security at home.”

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“By agreeing to this deal now on our terms, we’re securing strong protections, including from malign influence, that will allow the base to operate well into the next century, helping to keep us safe for generations to come,” Starmer told reporters at a UK military headquarters in Northwood, near London.

The agreement is expected to cost UK taxpayers billions, although the government has not provided specific figures. Concerns have been raised by critics over national security, pointing to Mauritius’s close trade ties with China. Conservative leader Kemi Badenoch labelled the decision as “Labour chaos,” accusing Keir Starmer’s government of “surrendering British territory” and placing a significant “burden” on taxpayers.

Foreign Office officials had cautioned that any further delay could damage the UK’s relations with both Mauritius and the United States. Despite the setback, Bertrice Pompe, who led the most recent legal challenge, pledged to persist in the campaign, stating, “We’re not Mauritians. We don’t want to give up our rights.”

Read | Historic! UK gives sovereignty of Chagos Island to Mauritius; India says ‘consistently supported…’

The transfer of sovereignty comes in the wake of a 2019 advisory opinion by the International Court of Justice, backed by the United Nations, which called on the UK to return the islands and bring an end to its colonial administration.

Where Are Chagos Island?

The Chagos Islands comprise a remote chain of over 60 islands situated in the middle of the Indian Ocean, off the southern tip of India and to the south of the Maldives. The islands have been under British sovereignty since 1814, when they were ceded by France.

The archipelago is perhaps most renowned for the military base on Diego Garcia, which has supported US military operations ranging from the Vietnam War to conflicts in Iraq and Afghanistan. In 2008, the US acknowledged that the base had also been used for secret rendition flights involving terror suspects.

In 1965, Britain separated the Chagos Islands from Mauritius, a former British colony, three years prior to Mauritius gaining independence, and designated the area as the British Indian Ocean Territory.

The US has described the base—home to approximately 2,500 personnel, predominantly American—as “an almost indispensable platform” for security operations across the Middle East, South Asia and East Africa.

More recently, the US deployed several nuclear-capable B-2 Spirit bombers to Diego Garcia amid an intense airstrike campaign targeting Yemen’s Houthi rebels.

Celebrations in Mauritius

The Chagos Refugees Group headquarters in Pointe aux Sables, near Port Louis, dozens of Chagossians came together to celebrate the signing of the  agreement. The atmosphere was charged with emotion — tears of joy were shed, firecrackers lit up the sky, and heartfelt tributes were exchanged. Speaking with BBC, one elderly woman, overwhelmed by the occasion, quietly said: “Now I can finally go there… and die in peace.”

Olivier Bancoult, the leader of the Chagos Refugees Group, described the occasion as “a historic day for us”.

“For years, talking to our children about Chagos felt like telling them a story about a place we never truly knew. Today, they will finally be able to walk the land of their ancestors,” he added.

Barrister Hisham Oozeer told the BBC the agreement represents a “win-win” — recognising Mauritius’ sovereignty over the Chagos Archipelago, including Diego Garcia, while also addressing the security interests of both the UK and the US.

“But at least after more than 50 years, today Mauritius is fully independent and all Mauritians reunited. Today we have on one side the sovereignty of Mauritius over the Chagos Islands being confirmed, and also the safety element, which was important for the UK and USA, being preserved,” he explained.

Covilen Narsinghen, president of the Mauritius Global Diaspora, described the event as a milestone — completing Mauritius’ decolonisation process and uniting all Mauritians under a single sovereign flag.

India Supports UK–Mauritius Deal

India has welcomed the treaty signed between Mauritius and the United Kingdom, which restores Mauritian sovereignty over the Chagos Archipelago, including Diego Garcia.

“The formal resolution of the longstanding Chagos dispute through this bilateral treaty is a milestone achievement and a positive development for the region. This is further to the understanding between the two sides reached in October 2024 and marks the culmination of the process of decolonisation of Mauritius in the spirit of international law and rules-based order,” the Ministry of External Affairs in New Delhi stated.

The MEA noted that India has consistently backed Mauritius’s rightful claim to the Chagos Archipelago, in line with its longstanding principles on decolonisation, respect for sovereignty, and the territorial integrity of nations.

“As a steadfast and longstanding partner of Mauritius, India remains committed to working closely with Mauritius and other like-minded countries to strengthen maritime security and regional stability and ensure peace and prosperity in the Indian Ocean region,” Randhir Jaiswal, the MEA spokesperson, stated.