The Chagos Archipelago Dispute: Decolonization, Sovereignty, Geopolitical Tensions

The Chagos Archipelago, a group of islands in the Indian Ocean, has been a longstanding point of contention between the United Kingdom and Mauritius. The conflict represents a complex geopolitical issue involving the United States. It centers on questions of sovereignty, colonial legacy, strategic military interests, and international law. 

Mauritius and Britain reached an agreement in October 2024 to transfer sovereignty over the Chagos Islands, which the UK retained after Mauritius gained independence in the 1960s. The deal stipulates that the UK-US military base on Diego Garcia, the largest island, would remain operational.  

After taking office in November, the Prime Minister of Mauritius, Navin Ramgoolam, restarted the negotiation process, reportedly seeking increased financial compensation and adjustments to the proposed 99-year lease. The current agreement offers a £90 million ($110 million) annual payment.

The deal has drawn criticism from some US officials, including Marco Rubio, Trump’s pick for secretary of state, who warned it posed “a serious threat” to national security.  

The UK government noted “We will only agree to a deal that protects the UK’s national security.”  The dispute remains unresolved.

Background and History

The Chagos Archipelago, a group of over 60 small islands, was originally part of the British colony of Mauritius. However, in 1965, three years before Mauritius gained independence in 1968, the UK separated the Chagos Archipelago to form the British Indian Ocean Territory (BIOT). This move violated United Nations resolutions that prohibited the dismemberment of colonies prior to their independence.

The UK subsequently leased the largest island in the Chagos Archipelago, Diego Garcia, to the United States in 1966 for the construction of a military base. To make way for the base, between 1967 and 1973, the indigenous Chagossian population, also known as Ilois, was forcibly removed from the islands and resettled in Mauritius and the Seychelles, often in dire conditions. 

International Law and Opinions 

Mauritius has consistently argued that the separation of the Chagos Archipelago was illegal under international law. The UN General Assembly has passed several resolutions supporting decolonization and calling for the UK to return the islands to Mauritius.

In 2019, the ICJ delivered a landmark advisory opinion stating that the UK’s continued administration of the Chagos Archipelago is unlawful and that the islands should be returned to Mauritius. The ICJ also highlighted the illegality of the Chagossian displacement.

Following the ICJ ruling, the UN General Assembly voted overwhelmingly in favor of a resolution demanding that the UK withdraw from the Chagos Archipelago and recognize Mauritius’s sovereignty. Despite this, the UK has refused to comply, arguing that it will cede sovereignty only when the islands are no longer needed for defense purposes.

U.S. Involvement in the Chagos Archipelago Dispute

The United States’ involvement in the Chagos dispute stems from its strategic interest in Diego Garcia, which hosts one of the most important U.S. military bases globally. The base is critical for U.S. operations in the Middle East, South Asia, and the Indo-Pacific region, serving as a logistics hub, a site for pre-positioned military supplies, and a platform for surveillance and power projection. 

While critical for global military operations, including logistics and surveillance, the U.S. has avoided taking a position on Mauritius’s sovereignty claims. Washington fears that a sovereignty transfer to Mauritius could complicate the legal and operational status of its base. To safeguard its access, the U.S. has consistently supported UK control over the Chagos Archipelago.

The U.S. has faced criticism for its indirect involvement in the displacement of the Chagossian people, who were forcibly removed to make way for the military base. Human rights advocates have called for accountability and reparations for the affected communities.

Mauritius’s Position and Actions

Mauritius has pursued international legal avenues, including the ICJ advisory opinion and arbitration under the United Nations Convention on the Law of the Sea (UNCLOS).

Mauritius has garnered significant international support, including backing from the African Union and many UN member states, for its claim over the Chagos Archipelago.

Mauritius has offered assurances that the U.S. could continue to operate its military base on Diego Garcia under a new arrangement, even if sovereignty is transferred. This proposal aims to alleviate U.S. concerns over strategic disruptions.

The UK’s Position

The UK has defended its administration of the Chagos Archipelago by citing its strategic importance and security agreements with the U.S. London argues that the territory remains vital for defense and counter-terrorism operations. However, the UK’s stance has been widely criticized as a remnant of colonial-era policies and as contrary to international law.

Conclusion

The Mauritius-UK conflict over the Chagos Archipelago highlights broader issues of decolonization, international law, and geopolitical strategy. While Mauritius has achieved significant legal and diplomatic victories, the UK’s refusal to relinquish control and the U.S.’s strategic interests in Diego Garcia have perpetuated the status quo.

Resolving the dispute will require balancing Mauritius’s rightful claims to sovereignty, the rights of the displaced Chagossians, and the strategic concerns of the U.S. and UK. A potential resolution could involve a sovereignty transfer to Mauritius while ensuring continued U.S. access to Diego Garcia through a lease agreement, aligning strategic and legal interests.

RESEARCHER: Hilal Oran