Britain should end its rule of a remote Indian Ocean archipelago that is home to a US military base as “rapidly as possible” after the United Nations’ highest court ruled that it had held the islands illegally for more than 50 years.
The UK forcibly removed about 2,000 people from the Chagos Islands in the 1960s and 1970s to clear the way for a strategically-important airbase of Diego Garcia in return for a cut-price missile deal with the United States.
Many of the islanders resettled in Britain where they have continued to fight for a return to their homeland.
Their case received strong backing on Monday after UN judges ruled that the islands had been taken unlawfully from Mauritius three years before the island nation was given its independence in 1968.
The ruling is not binding but it increases pressure on the UK to act after the UN General Assembly asked the court to look into the issue.
The high-level rebuke of Britain's post-colonial strategy comes at an awkward time as the UK seeks to assert itself as significant world force with its “Global Britain” strategy after Brexit.
Britain had insisted that it had sovereignty over the archipelago – which it calls the British Indian Ocean Territory – but was rebuffed by the court which called on all UN member states to ensure the islands were returned to their rightful owners.
“The United Kingdom is under an obligation to bring an end to its administration of the Chagos Archipelago as rapidly as possible, thereby allowing Mauritius to complete the decolonisation of its territory,” chief judge Abdulqawi Ahmed Yusuf said.
The ruling followed a four-day hearing last year. The court heard claims from Mauritius officials that they had been coerced into giving up a large swathe of their territory before independence during a meeting in London.
Former islanders also told the court they were “uprooted like animals” and loaded on to a ship away from the island.
The evictions were described in a British diplomatic cable at the time as the removal of a “few Tarzans and Man Fridays".
“When this was done, it was done in the dark,” said Liseby Elysé, 65. “And when we boarded the ship, conditions in the hull of the ship were bad. We were like animals and slaves in that ship.”
The UK has repeatedly refused to allow their return using blocking tactics that included creating a huge marine reserve to prevent any resettlement.
Meanwhile Diego Garcia has been a strategically vital site for the US that has been used as a base from which aircraft took off and refuelled during wars in Iraq and Afghanistan.
The islanders had long been frustrated in their attempts to win a return through the courts in Britain which had repeatedly ruled against the islanders.
Britain maintained that Mauritius had given up the islands willingly but accepted that the way that islanders “were treated was shameful and wrong”. It said it had invested £40 million in resettlement programmes but the islanders have continued to press for a return home.
A study carried out by the Foreign Office in 2015 found that 98 per cent of the exiles and their families were in favour of resettlement, with the majority saying they would be happy to have jobs working with the military on Diego Garcia.
After the case was referred to the International Court of Justice, the United States said that it would not take a position on the dispute.
The UN judges found on Monday that the agreement struck between Britain had not been “based on the free and genuine expression of the will of the people concerned” and that the break-up of the colony was against international law.
A British Foreign Office spokesperson said the ruling was "an advisory opinion, not a judgement" but would examine it carefully.