We tend to think that the era of colonialism is over. However, while most of the European colonial powers gave up their holdings in the 1960s, 70s and 80s, the process was not so complete. One of the most interesting examples in modern international relations is the case of Chagos Archipelago, located approximately 500 kms south of Maldives and 1900 km south west of Indian southernmost tip, strategically located in the Central Indian Ocean. Mauritius is now all set to take over charge of the Chagos islands held by United Kingdom (UK) from the colonial past.
Presently, controlled and administered by the UK, the Chagos islands or the Chagos Archipelago encompass seven atolls comprising of 60 or more strategically important islands in the centre of the Indian Ocean over an area of 56.13 sq kms. One of the last vestiges of the British Empire oversea territories, the area was called the British Indian Ocean Territory [BIOT]. The largest island is Diego Garcia in the South East with an area of 32.5 sq kms, located in between Africa, India and South East Asia.
Strategic Importance and Military Base
Being one of the most isolated uninhabited islands in the world and in a very useful location for a military base, their remoteness minimises the risk of surveillance. Because of its exceptional biodiversity of undersea geological features like deep trenches and oceanic ridges, the archipelago is unique and one of its kind in the world. An added advantage is that the area is not affected by cyclones and tropical storms. All this helped in selecting Diego Garcia as home to a joint UK-US military base which is crucial for US operations in the Indian ocean and Indo-Pacific region. Mauritius has always claimed that it was forced to give up the islands in exchange for its freedom in 1968.
Colonial History
The history of the Chagos islands is deeply connected and intertwined with the history of European colonisation. In the 16th century, the Portuguese discovered the then uninhabited islands. In late 18th century, the islands were taken over by France. France already had a colony, Mauritius further South. Slaves were moved from Africa, Seychelles and India to grow coconut plantations from where produce was sent to Europe. After the treaty of Paris in 1814 and the defeat of Napolean at Waterloo at the end of the Napoleonic wars, UK gained control of the territories of Mauritius and Chagos islands. They were administered by the colonial Government on the island of Mauritius until 1965 when UK purchased them as a separate British overseas territory. UK split the Chagos islands from Mauritius along with three islands from Seychelles to form the BIOT.
While the Chagos handover is framed as a victory for Mauritius, the real winner may be Washington—securing 99 more years of Diego Garcia’s critical airfield. But as China expands its footprint across the Indo-Pacific and the Global South asserts its sovereignty, holding strategic assets through Western proxies is becoming increasingly untenable
Cold War Era and Forced Evictions
After the 2nd World War, the world fell into a period of Cold war between the US and the Soviet Union along with their allies. Both sides were trying to get a strategic advantage over each other. Mauritius was granted independence in 1968. Before granting independence to Mauritius, UK paid 3 million pounds in compensation with a commitment that the islands would be returned to Mauritius if no longer required for defence purposes.
On December 30, 1966, a secret deal was struck between US and UK which permitted the United States Armed Forces to use any island of the BIOT for defence purposes for 50 years, until December 2016, followed by a 20 years optional extension to 2036. However, only Diego Garcia was transformed into a military base. 1500 original inhabitants of the islands were forcibly expelled between 1967 and 1973 to make way for the base. Known as Chagossians, they are now mainly settled in Mauritius, Seychelles and the UK. Subsequently, the plantations on the islands were shut down and it became unlawful for a person to enter or remain in Diego Garcia without a permit.
Diego Garcia, the largest in the archipelago, became a fully operational military base in 1986. It was a key location in the US overseas “war on terror” operations following Al-Qaeda’s 9/11 attacks on the US in 2001.
Legal Battles and International Pressure
Mauritius has since been engaged in a sovereignty dispute with UK. In 1982, the UK Government agreed to pay 4 million pounds into a trust fund for the Chagossians, to be set up under a Mauritian statute. In 2000, the UK High Court found the expulsion of the Chagossians to be unlawful. However, in 2008 the house of commons, UK’s highest court decided against the right of the return of Chagossians, overturning a series of decisions by lower courts that had found their exile to be unlawful.
Only as late as 2019, the International Court of Justice (ICJ), in a nonbinding advisory opinion ruled that UK’s continued administration of the Chagos islands was illegal and called for the islands return to Mauritius. US along with 5 members voted against the resolution while 116 members were for Mauritius to be given back the Chagos islands. The question of original nativity of the Chagossians was also raked up by UK claiming that that they had come to the islands from other countries as workers.
Despite international pressure, UK did not abide by the resolution. The United Nations General Assembly followed this with a resolution affirming Mauritius’s sovereignty over Chagos and demanded UK’s withdrawal. Over the past few years, there has been mounting pressure on UK to surrender the islands. UK chose to delay the inevitable in 2010 by declaring a marine protected area around Chagos islands in an effort to ensure that no islanders can settle there. However, the Permanent Court of Arbitration ruled against it in 2015.
Non adherence of the ruling of ICJ was having an increasingly adverse effect on UK’s political, legal and diplomatic standing in international affairs. It also faced diplomatic isolation on its claim that Mauritius had no legitimate claim to the island.
Diego Garcia is the linchpin of Western strategy from the Middle East to the Malacca Straits. That’s why Washington fought so hard to keep it, even as Britain faced mounting isolation over its colonial holdout
The 2024 Agreement
On October 3, 2024, UK and Mauritius reached a long overdue political agreement where Mauritius will get sovereignty over the Chagos archipelago including Diego Garcia, but UK would retain the right to exercise rights over Diego Garcia for an initial period of 99 years to ensure the continued operation of the base. In February 2025, President Trump was also inclined to approve the deal.
This secures and guarantees the future of the operation of Diego Garcia base which has been central to the territorial dispute. It is an axis to the Indo Pacific region. The military base houses Naval ports and air strips for Bomber aircraft which UK and US consider essential for maintaining strategic balance in the area. UK will pay 160 million dollars a year for 99 years to lease back Diego Garcia and allow the military base to stay. It will secure the future of the archipelagos people who will now have the right to return to Chagos islands except for Diego Garcia which will remain off limits.
As per “the Newsmen” dated March 28, 2025, this will address UK’s concerns as Mauritius would take full responsibility for the route via Indian Ocean being used by illegal immigrants to go to UK. As late as on March 26, 2025, B-2 Bombers have been postured at Diego Garcia in planning for military action on the Houthis and Iran in the near future.
International Reactions and India’s Role
India played a quiet but important role in finalising a deal in UK handing over sovereignty of the Chagos islands after half a century and has called the outcome a win for all sides. India has always played a major role in raising a voice against colonialism in the world in open support. India’s External Affairs Minister on his visit to Mauritius had stated that “India has always given its constant support to Mauritius in line with its principle stand on de colonialism and support for sovereignty and territorial integrity of Nations”.
In a White House statement, Joe Biden also articulated that “It is a clear demonstration that through diplomacy and partnership, countries can overcome long standing historical challenges to reach peaceful and mutually beneficial outcomes”.
Geopolitical Implications
The impact and significance of the Chagos islands and the dispute over their sovereignty is far greater than many might realise. Geopolitical forces shaped negotiations over the future of the islands. However, security concerns remain with many in UK calling the deal a strategic disaster for UK.
China has a burgeoning economic relationship with the nearest located country Maldives which could compromise the base. It could be used by China to expand its influence in the Indian ocean by establishing its own rival base. The dispute has also been seen by some as a symbol of the declining influence of UK and US in the World.
With the agreement on handing over of Britain’s last African colony, the other British territories can only wait for the sun to set on their shore.
The writer is an armed forces veteran who has been an instructor at OTA, Chennai and Army War College, Mhow. He has commanded an Infantry Battalion Group with UN in Sudan and an Infantry Brigade in the Northern Sector
