Diego Garcia was never a “suitable long-term location for migrants” and the government “inherited a deeply troubling situation that remained unresolved under the last administration for years”, the spokesperson added.

Lawyer Simon Robinson with UK firm Duncan Lewis, which is representing some of the migrants, said “questions need to be answered about how, in the 21st century, this was able to happen”.

The ruling follows a landmark hearing held in a converted chapel on the island in September. The BBC gained unprecedented access to the island and the migrant camp there to cover the proceedings.

Diego Garcia is part of the Chagos Islands, or British Indian Ocean Territory (Biot), an area described as being “constitutionally distinct” from the UK. It is administered from London by a commissioner based out of the Foreign Office.

In their time on the island, the Tamils, including 16 children, were housed in military tents in the fenced camp, which was guarded at all times by private security company G4S.

Tamils have described their time on the island as like living in “hell”.

“It’s like an open prison – we were not allowed to go outside, we were just living in a fence and in a tent,” one woman told the BBC after being brought to the UK with her husband and two children this month.

During a site visit to the camp in September, the court saw rips in some of the tents and rats nesting above military cots that the migrants were given as beds.

There were multiple hunger strikes and numerous incidents of self-harm and suicide attempts in response to the conditions in the camp, after which some people were transferred to Rwanda for medical treatment.

There were also cases and allegations of sexual assault and harassment within the camp by other migrants, including against children.