The Chagos Archipelago sits at the nexus of decolonisation, international law, and global military strategy. Disputed betwMauritius and the United Kingdom, the islands have become a flashpoint for debates on self-determination and post-colonial territorial integrity. While Mauritius argues that the islands are an inalienable part of its territory, the UK maintains its sovereignty, asserting that the islands will eventually be transferred once they are no longer required for military purposes.
In a dramatic twist, just three months into power, the Labour government celebrated what it described as a diplomatic coup. This move effectively ended a long-running dispute over one of Britain’s “last imperial possessions,” while safeguarding a joint UK-US military base on Diego Garcia for decades to come. Yet, the decision has not been met with universal acclaim. The transfer of what is often dubbed Britain’s “last African colony” to Mauritius has sparked deep opposition, mistrust, and disappointment from multiple quarters—even drawing criticism from members of the Trump administration in the US.
Mauritius, a history
Mauritius is renowned as one of the world’s most multicultural societies. Its people are largely descendants of Indian labourers, Chinese traders, African slaves, and colonists from the Dutch, French, and British empires. Although Arab and Malay sailors likely visited as early as the 10th century, Mauritius’s recorded history begins in the 16th century. It was a Portuguese sailor, Don Pedro Mascarenhas, who encountered the island in 1512, although he may not have been the first European to set foot there.
In 1598, a Dutch squadron under Admiral Wybrand Van Warwyck landed at Grand Port and named the island after Prince Maurits van Nassau, the stadtholder of Holland. By 1638, the Dutch had established a settlement, using the island as a base for exploring Australia’s western coast. Even after the Dutch left Mauritius in 1710, their influence endured through the introduction of sugarcane, domestic animals, and deer.
Five years later, the French arrived. Landing in 1715, they renamed the island ‘Isle de France’ and established Port Louis as both a naval base and a shipbuilding centre. Under French rule, Mauritius saw an influx of African slaves and the growth of a prosperous sugar industry. The British administration, which began in 1810 with Governor Robert Townsend Farquhar, introduced rapid social and economic reforms, most notably, the abolition of slavery in 1835. Compensation for the loss of slave labour, paid by the Bank of England on behalf of the British government, set in motion what became known as the ‘Great Experiment.’
This experiment highlighted the supposed superiority of free labour over slave labour in plantation colonies, attracting an estimated 462,000 indentured labourers from India, China, Comoros, Madagascar, Mozambique, and Southeast Asia between 1835 and the First World War. Their arrival not only transformed the island’s economy but also its social fabric.
Sovereignty of the Chagos Archipelago
In 1965, as Mauritius edged closer to independence, the United Kingdom split the Chagos Archipelago away from Mauritius, with the Mauritian government’s agreement, to form the British Indian Ocean Territory. The new territory also initially included the islands of Aldabra, Farquhar, and Desroches (the latter later returned to the Seychelles upon independence in 1976). Despite these changes, the British retained control of Diego Garcia, an island that now hosts a sprawling US-UK military base and plays a critical role in regional security.
Recent international political pressures pushed the UK to discuss transferring sovereignty over the Chagos Islands to Mauritius. This move is coupled with a 99-year lease for the Diego Garcia base, ensuring its continued strategic utility. On October 3, 2024, the UK announced that it would cede sovereignty over the Chagos Archipelago to Mauritius.
On the strategic front, the utility of the joint US-UK military base on Diego Garcia has been legally secured with the lease. As UK negotiator Jonathan Powell explained on X, “This deal was reached in close consultation with US officials and puts the base on legally safe ground for the first time in decades.”
The dual goals of the agreement are clear: to safeguard the security and operational utility of the military base while also aiming to benefit Chagossians—who were displaced in 1965 when the islands were separated from Mauritius to facilitate its independence.
However, the decision has proved deeply controversial within the UK. Critics ranging from former Conservative government ministers to various international commentators have labelled the move “naive” and “dangerous,” arguing that it represents a blow to British prestige.
Although the announcement’s apparent suddenness – coming just three months after the Labour government assumed power – suggests haste, the decision is, in fact, the result of a lengthy, complex negotiation process. It is worth noting that a previous Conservative government had already embarked on negotiations after Mauritius brought the matter before the International Court of Justice, which in 2019 issued a non-binding opinion favouring Mauritius.
US President Donald Trump had back then led a diplomatic offensive at the United Nations to bolster the UK’s claim over the islands. The initiative, however, met with limited success with only three nations, all close political allies of Trump (Israel under Benjamin Netanyahu, Hungary under Viktor Orbán, and Australia under Scott Morrison), supporting the US-UK position. Major international players such as Canada, New Zealand, most members of the North Atlantic Treaty Organisation (NATO), Japan, and the Republic of Korea abstained.
Later that year, the UN General Assembly voted 116 in favour to six against—with 56 abstentions—on a resolution welcoming the February 25, 2019, International Court of Justice advisory opinion on the legal consequences of separating the Chagos Archipelago from Mauritius. The resolution demanded that the UK unconditionally withdraw its colonial administration from the Chagos Archipelago within six months, allowing Mauritius to complete its decolonisation process.
After a change of government in Mauritius in November 2024, negotiations on the Chagos Islands were reopened in December 2024. Although Mauritius initially sought higher rental fees for the Diego Garcia base, the rental issue appears to have been resolved this month (February 2025), with reports indicating a total payment of around £9 billion over the lease’s 99-year term.
Strategic considerations
The strategic importance of Diego Garcia cannot be overstated. According to an article in Foreign Policy magazine, “Thanks to its vital location, the island houses a military base that served as a critical node for American air operations during the Gulf War and the wars in Iraq and Afghanistan. Post-9/11, it has also been allegedly used as a detention centre by the [US intelligence agency] CIA.” This underscores the long-standing military significance of the island.
Yet, the implications extend far beyond military logistics. Analysts express concerns that the decision to transfer sovereignty may embolden regional competitors. There are fears that China, for example, could develop commercial ports in the region to rival India’s growing economic influence. As Samir Puri of the international think tank Chatham House noted, “This is a long-term matter of concern to monitor, regardless of the UK’s decision on Chagos.”
Adding another layer to the geopolitical calculus, Luke de Pulford, Executive Director of the Inter-Parliamentary Alliance on China, told the politics and policy news organisation POLITICO, “Recent years have demonstrated beyond doubt China’s willingness to use their leverage to get what they want from strategic partners.” His comments come as evidence of Chinese support for Mauritius becomes increasingly visible.
For instance, a major airport in Mauritius was completed in 2013 with a £197 million loan from Beijing, and reports indicate that China has helped construct key infrastructure projects including the state broadcaster’s headquarters, a dam, and a sports complex. Notably, Mauritius was also the first African nation to sign and activate a free trade agreement with Beijing.
The transfer of sovereignty over the Chagos Islands also invites comparisons with another historic handover – Hong Kong’s return to China in 1997. Under the “one country, two systems” framework, Hong Kong was promised freedoms including freedom of speech, an independent judiciary, and multiple political parties until 2047. However, these assurances were eventually undermined by Beijing’s policies.
Despite these challenges, strategic considerations in the Indian Ocean differ markedly from those in the Pacific. The Chagos Islands lie in close proximity to India, and the country has welcomed the UK’s decision. “In the long run, it is likely that India will play a leading role in Indian Ocean security, and the UK will want to be well-placed to explore how to play a role as an effective partner,” writes Puri.
Meanwhile, the UK has reassured its critics by insisting that the decision regarding the Chagos Islands is a one-off move—distinct from its stance on other overseas territories such as the Falkland Islands and Gibraltar, whose statuses “are not up for negotiation,” according to Foreign Secretary David Lammy.
The saga of the Chagos Islands encapsulates the complexities of decolonisation, international law, and strategic military planning. As Mauritius and the UK navigate their intertwined histories and future aspirations, the dispute over the Chagos Archipelago remains a potent symbol of both the lingering legacies of the empire and the evolving dynamics of global geopolitics.
The dispute between the UK and Mauritius is long ranging 
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