Few defence-related decisions spark such heated debate as the future of Diego Garcia. For many, the idea of the UK handing over any territory feels unacceptable.
But the legal and geopolitical context surrounding this issue is far more complex than headlines alone suggest.
A Complicated Legal Legacy
The United Kingdom’s sovereignty over the Chagos Archipelago, of which Diego Garcia is a part, has been increasingly challenged through a series of international legal proceedings. These include rulings from:
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The International Court of Justice (ICJ)
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The United Nations General Assembly
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The International Tribunal for the Law of the Sea
While these decisions have been described as non-binding, the growing momentum behind Mauritius’ legal case posed a very real and escalating threat. A fresh, legally binding ruling in favour of Mauritius was a credible and imminent possibility—one that could have compromised not only the UK’s sovereignty, but also the continued operation of the strategic US-UK military base on Diego Garcia.
Strategic Imperatives and Legal Risk
Historically, Britain governed the Chagos Islands from Mauritius, after assuming control from the French in 1810. Just before Mauritius gained independence, the UK separated governance of the islands to facilitate construction of the military base in partnership with the United States.
This decision, however, became the subject of international legal challenges. And critically, those challenges never fully abated. With legal momentum building in favour of Mauritius, the risk was no longer hypothetical.
Should the UK have lost a binding case, it might not only have faced the loss of territory—but also the right to operate one of the West’s most strategically important overseas military installations. Diego Garcia remains a linchpin in America’s global military posture, serving as a forward-operating hub in the Indo-Pacific.
This is why US President Donald Trump—who understands the nature of transactional diplomacy—considered the 99-year access agreement “a good deal.” It guarantees continued operational security for both US and UK forces, while averting a potentially damaging legal defeat.
Global Order and the Consequences of Inaction
We must also look at this through the broader lens of global security. The rules-based international order is increasingly under strain. For the UK, a permanent member of the UN Security Council, to ignore the rule of international law would signal a retreat from our standing as a responsible global actor.
To dismiss a binding ruling would not only undermine our legal credibility but also play directly into the hands of adversaries like China and Russia—nations actively pursuing expansionist claims in the South China Sea and the Arctic, often in defiance of international norms.
An Imperfect but Strategic Outcome
This agreement is not without flaws, and it is right that the financial arrangements be subject to public and parliamentary scrutiny. Yet, given the strategic stakes and legal trajectory, this was a necessary decision.
To risk the loss of Diego Garcia—and with it, a cornerstone of our Indo-Pacific security strategy—would have been deeply short-sighted.
At UDSS, we view this outcome through a strategic lens. In a period of increasing geopolitical volatility, retaining assured access to Diego Garcia protects our shared security interests with the United States and sustains the UK’s role in underpinning global stability.
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