Court of Appeal upholds ruling that asylum seekers were unlawfully detained on British Indian Ocean Territory of Diego Garcia

The ruling was made in a judgment handed down on Tuesday 16 December 2025, exactly a year since the Supreme Court of the British Indian Ocean Territory ruled that the asylum seekers had been unlawfully detained, a judgment that the BIOT Commissioner had appealed.

The Commissioner’s appeal was dismissed on all grounds.

Lawyers representing the asylum seekers said the judgment was a complete vindication for the ruling in the lower court made by Ms Justice Obi after a full trial on the island of Diego Garcia.

The Commissioner had argued that the Claimants had never been detained on Diego Garcia but had been excluded for their own safety from entering the military base. He said their detention was lawful because of Restricted Movement Orders he had imposed.

He told the Court of Appeal that the Supreme Court had failed to have proper regard for the exceptional circumstances on Diego Garcia. He said the judge had failed to determine whether confinement had been direct and intentional.

However, the Court of Appeal ruled it was satisfied that the Supreme Court had been fully aware of the exceptional circumstances. It said the Supreme Court had considered ‘head on’ whether the detention was direct and intentional and had correctly concluded it was.

It ruled that there were “physical barriers, in the form of the wire fence; people, in the form of G4S officers, who guarded the camp and forcibly returned absconders; threats of force and legal process, pursuant to the RMOs; and punishments for absconding. The Commissioner continued to prevent the Claimants from leaving the Camp even after they had been granted interim relief by this Court on 23 April 2024.” The BIOT CA acknowledged that the Commissioner “had to manage a situation that he did not want” but concluded that SC had been correct to find that the Commissioner had intended to confine the Claimants and their confinement amounted to detention.

It added: “The SC had been fully aware throughout of the security issues pertaining on Diego Garcia. There was no reason to interfere with the SC’s decision.”

Leigh Day human rights team lawyers Tom Short, Tessa Gregory and Claire Powell represent six of the 12 claimants who brought the successful judicial review claim which the Commissioner had sought to overturn. Leigh Day also represents a further 33 individuals with separate claims concerning their detention on the island whose rights are vindicated by this ruling. Leigh Day has represented the group of asylum seekers since their plight became known early in 2022. They were brought to Diego Garcia, which hosts a US military base, in early October 2021, after the boat on which they were travelling foundered at sea.  On arrival, they were immediately placed in detention in a fenced and guarded camp the size of a small cricket field, and were prevented from leaving for the next three years. All of the group made claims for international protection on arrival at Diego Garcia.  

After a three-year legal battle, the group were finally transferred to the UK in November 2024.  At the time of their transfer to the UK, the BIOT Commissioner had still not determined all but a handful of the claims for international protection.

Leigh Day solicitor Tom Short said:

“The BIOT Court of Appeal’s ruling that the Commissioner unlawfully detained our clients for over three years in a fenced and guarded camp in conditions that amounted to a prison is full vindication of the judgment made earlier by Ms Justice Obi after a full trial on the island of Diego Garcia.

"The Court has found that the Commissioner intended to confine our clients – including 16 children – in this way and that he had no justification for doing so. His attempt to rewrite history has failed.

"We hope that this will be the end of the matter and that no further public money will be wasted by the British Indian Ocean Territory Administration in trying to deny the reality that the Commissioner treated our vulnerable clients as prisoners.”