Sri Lankan Tamils’ Detention by UK–US Authorities Ruled Unlawful
London — A year after a court first described their confinement as “hell on Earth,” Sri Lankan Tamil asylum seekers detained on Diego Garcia have secured a decisive legal victory that reverberates far beyond a remote atoll in the Indian Ocean. On Tuesday, the British Indian Ocean Territory (BIOT) Court of Appeal rejected every ground of appeal brought by the territory’s commissioner, confirming that dozens of Tamils — including children — were unlawfully detained for more than three years on a UK–US military base. The ruling sharpens uncomfortable questions for London and Washington alike, and places the Sri Lankan government under renewed diplomatic and legal pressure to confront the consequences for its citizens.
The judgment, handed down in a London court, upheld a landmark decision delivered exactly a year earlier, on 16 December 2024, by Ms Justice Obi. That ruling found that the Tamils, survivors of a shipwreck while attempting to reach Canada to seek asylum, had been unlawfully confined on Diego Garcia in conditions amounting to imprisonment. The Court of Appeal’s dismissal of the commissioner’s challenge — in full — closes the door on efforts to reframe the episode as an unavoidable administrative response to an emergency at sea.
A remote island, a legal vacuum
Diego Garcia is among the world’s most isolated places: a coral atoll ringed by military secrecy, leased by the United Kingdom to the United States and used as a strategic hub for operations across the Middle East and Asia. It has never been a civilian settlement, nor a place designed to receive migrants. That fact, the Foreign, Commonwealth and Development Office (FCDO) now concedes, lay at the heart of the problem.
Yet the absence of suitability did not absolve the authorities of their legal obligations. The asylum seekers — Sri Lankan Tamils fleeing persecution — arrived after a shipwreck left them with no alternative but to disembark on the atoll. What followed was not a brief humanitarian pause, but prolonged confinement behind fences and guards, with movement restricted and lives placed in indefinite suspension.
The Court of Appeal was unequivocal: the commissioner intended to confine the group, including 16 children, and did so without lawful justification. Evidence advanced to suggest otherwise was described by the judges as “a highly selective exercise,” a pointed rebuke that signals judicial impatience with post hoc rationalisations.
“Full vindication”
For the claimants’ legal teams, the ruling represents more than technical victory. Tom Short of Leigh Day, representing some of the Tamils, described Tuesday’s judgment as “full vindication” of the original trial findings. The court, he said, had confirmed that the detention amounted to imprisonment and that attempts to rewrite the narrative had failed.
Simon Robinson of Duncan Lewis Solicitors echoed that assessment, emphasising both the human and financial costs. The unlawful detention, he noted, ran to £108,000 per day for the UK taxpayer. With substantial damages now likely to be awarded, the bill will rise further — an escalation driven, in Robinson’s words, by “egregious delay” at the highest political levels in ending the detention and arranging relocation.
The language is notable. Courts are typically restrained when assessing executive decision-making in sensitive contexts involving national security and foreign affairs. Here, however, the judges were prepared to scrutinise intent, duration, and conditions, and to conclude that the line into unlawfulness had been crossed early and remained so throughout.
A shared responsibility
While the BIOT administration formally bears responsibility for the territory, Diego Garcia’s reality is inescapably binational. The atoll’s strategic purpose — and the constraints it imposes — flow from the UK–US defence arrangement that has shaped the island for decades. Although the litigation focused on the commissioner’s actions, the moral and political responsibility is shared.
Washington has remained publicly muted, allowing London to carry the legal exposure. Yet the presence of a US base, the operational control exercised by American forces, and the security perimeter that defined the detainees’ daily existence all form part of the factual matrix. The ruling will therefore be read in capitals far beyond London, not least Colombo.
Implications for Sri Lanka
For Sri Lanka, the decision introduces a new and uncomfortable outcome. Its citizens were unlawfully detained by foreign authorities for years, including minors, in conditions condemned by a British court. Colombo can no longer plausibly frame the episode as an unfortunate but lawful by-product of irregular migration.
The Sri Lankan government now faces several choices. At a minimum, it must seek full consular accounting: how decisions were taken, what representations were made, and why alternatives were not pursued sooner. There is also the question of diplomatic redress. While damages will be paid to the claimants by the detaining authority, Sri Lanka has grounds to demand assurances — and potentially agreements — to prevent any recurrence involving its nationals.
More broadly, the ruling strengthens the hand of Tamil advocacy groups who have long argued that Sri Lankan asylum seekers face systemic risks abroad compounded by indifference at home. The judgment’s findings on intent and duration undermine narratives that portray such detentions as neutral holding measures rather than coercive confinement.
Children behind fences
Perhaps the most troubling aspect of the case is the detention of children. Sixteen minors spent formative years behind fences on a military base never designed for family life. The Court of Appeal’s endorsement of the trial judge’s findings leaves little room for euphemism: this was not care, but confinement.
International law draws a bright line around the detention of children, particularly asylum-seeking children. States are required to treat detention as a last resort and for the shortest appropriate period. Three years on Diego Garcia cannot plausibly meet that standard. The ruling therefore resonates with wider debates about the treatment of migrant children across jurisdictions, from offshore processing to hotel detention.
The cost of delay
Financially, the case is a cautionary tale about the price of indecision. At £108,000 per day, the cost of maintaining a guarded camp on a remote atoll quickly dwarfed the expense of humane alternatives. Add to this the damages now likely to be awarded, and the episode stands as an object lesson in how delay magnifies liability.
Politically, the delay exposed fractures within government. Responsibility was diffused between the Home Office, the FCDO, and the BIOT administration, allowing inertia to masquerade as caution. The Court of Appeal’s judgment cuts through that diffusion, fixing responsibility squarely on the authority that ordered and maintained the detention.
The government response
The FCDO’s response was measured but revealing. A spokesperson acknowledged that Diego Garcia “has never been a suitable location for migrants” and characterised the situation as “highly unique,” stressing that safety had been carefully considered. Yet the statement concluded with an admission: “This is clearly not the outcome we wanted.”
That candour underscores the stakes. The outcome the government wanted — judicial endorsement of its actions — has not materialised. Instead, the courts have affirmed that legal standards apply even in the most unusual circumstances, and that remoteness does not confer immunity.
Beyond Diego Garcia
The ramifications extend beyond this single group of Tamils. The judgment will inform how courts assess detention in other extraterritorial contexts, including offshore processing arrangements and military installations. It reinforces the principle that where a state exercises effective control, it cannot sidestep its obligations by pointing to geography or security.
For asylum policy, the ruling complicates narratives that frame deterrence as administrative necessity. The court’s emphasis on intent — the decision to confine — signals that motives matter. Where confinement is chosen, rather than unavoidable, the law will scrutinise both justification and proportionality.
A reckoning for policy-makers
There is also a reckoning for policy-makers who have treated migration crises as episodic emergencies rather than structural challenges requiring durable frameworks. The absence of a pre-agreed protocol for shipwreck survivors in a territory like BIOT created the conditions for unlawful detention. Planning failures became legal liabilities.
In this sense, the case mirrors broader debates about flood control, climate displacement, and crisis preparedness. Exceptional circumstances are no longer exceptional when they recur. Legal systems are increasingly unwilling to indulge improvisation that infringes fundamental rights.
What comes next
Practically, the BIOT administration must now “study the judgment carefully” and consider next steps. Appeals beyond the territory’s court system appear unlikely to succeed given the clarity of the findings. Attention will therefore turn to damages, apologies, and institutional reform.
For the Tamils themselves, the judgment cannot restore lost years. But it does offer recognition — a formal acknowledgment that what they endured was not merely harsh, but unlawful. In the lexicon of human rights law, that distinction matter
The Court of Appeal’s decision marks a watershed in the long-running saga of the Diego Garcia detainees. It confirms that even on one of the world’s most remote islands, behind the fences of a military base, the rule of law persists. For the United Kingdom, it is a sobering reminder that legal obligations travel with power. For the United States, it is a prompt to reflect on the human consequences of shared facilities and shared control. And for Sri Lanka, it is a call to engage — robustly and transparently — when its citizens are wronged abroad.
Above all, the judgment affirms a simple proposition with far-reaching implications: there are no legal black holes. Geography does not erase rights, and remoteness does not excuse injustice.