A senior United States senator has publicly urged the United Kingdom to abandon its planned transfer of sovereignty over the Chagos Islands to Mauritius, arguing that the arrangement risks undermining the long-term security of a key joint military facility in the Indian Ocean.

Republican Senator John Kennedy of Louisiana made his appeal in a high-profile op-ed and subsequent statements, asserting that the current deal negotiated by the Labour government under Prime Minister Keir Starmer constitutes a strategic misstep and could embolden geopolitical rivals.

In his commentary, the senator criticised the terms of the Chagos sovereignty agreement, under which the UK would cede formal control of the archipelago — including the strategically located island of Diego Garcia — to Mauritius while securing a leaseback of the territory that hosts a vital US-UK military base.

Kennedy described the plan as a threat to shared security interests and urged Starmer to reconsider the arrangement, framing the issue as central to the defence partnership between Washington and London.

He contended that relinquishing sovereignty, even with a lease in place, could expose the base’s operations to future legal or political challenges, particularly as international dynamics evolve.

Kennedy’s intervention aligns with broader criticism from some American policymakers who have called for closer coordination between allied governments on matters affecting joint defence infrastructure.

In his advocacy, the senator highlighted concerns that China and Russia could exploit any perceived weakening of control over the Indian Ocean territory, reflecting strategic competition in the region.

He has also publicly supported former US President Donald Trump’s denunciations of the UK’s approach, characterising the transfer as counter to Western security interests and cautioning that it could form part of the legacy of Starmer’s administration if allowed to proceed.

The UK government has maintained that the treaty with Mauritius — first agreed in May 2025 — is designed to secure the future of the Diego Garcia base while complying with international legal pressures and addressing longstanding disputes over sovereignty.

Under the terms negotiated, the UK and its US partner retain a lease on Diego Garcia for at least ninety-nine years, with provisions intended to safeguard the base’s operational stability.

London has insisted that the arrangement does not compromise national or allied security and has been endorsed by senior military and diplomatic officials.

Despite these assurances, Kennedy’s comments have injected fresh tension into a high-stakes geopolitical debate.

His call for Starmer to “ditch the Chagos deal for good” reflects a faction of opinion in Washington that views the arrangement as risky and unnecessary in the context of great-power competition.

The exchange underscores the complexities faced by allied governments in balancing historical legal disputes, international diplomacy and the strategic imperatives of defence partnerships in an increasingly contested global environment.