Britain must return the Chagos Islands to Mauritius as “rapidly as possible,” the United Nation’s top court ruled Monday, saying that Britain’s continued occupation of the Indian Ocean archipelago is illegal.
The islands, which are home to the strategic U.S. military base, Diego Garcia, were separated from the former British territory of Mauritius during decolonization in 1968.
The International Court of Justice (ICJ) has, however, ruled that the separation was illegal under international law and had not been based on a “free and genuine expression of the people concerned”.
“This continued administration constitutes a wrongful act,” said the president of the ICJ, Abdulqawi Ahmed Yusuf while delivering judgement.
“The UK has an obligation to bring to an end its administration of the Chagos archipelago as rapidly as possible and that all member states must co-operate with the United Nations to complete the decolonization of Mauritius.”
Mauritius was a British colony from 1810 until 1968, when it achieved independence and became a republic. Ahead of this independence, the UK held talks with the U.S. on the “strategic use of certain small, British-owned islands in the Indian Ocean” for defense purposes, the court said.
“During these talks, the United States expressed an interest in establishing a military communication facility on Diego Garcia,” the court added.
During the decolonization process, London decided that the Chagos archipelago would be separated from the rest of Mauritius and incorporated into a separate colony, referred to as the British Indian Ocean Territory, according to a CNN report.
The separation, according to Mauritius in a submission to the court, was carried out “without any regard to the will of the people of Mauritius, including those who lived in the Chagos Archipelago.”
Mauritius had argued in court last year that it was coerced into giving up the Chagos Islands. According to its lawyers, the separation was at variance with a UN resolution passed in 1960, which specifically banned the breakup of colonies before independence.
As part of the separation process, the entire population of Chagos Islands (about 1,500) was deported and never allowed to return home. The island was then leased to the U.S. for the airbase in 1971. The airbase serves as a landing spot for bombers that fly missions across Asia, including over the South China Sea, said a CNN report.
In the 1980s, the UK paid an estimated $5.2 million to more than 1,300 evicted islanders, on the condition they sign or place a thumbprint on a form renouncing their right to return to the Chagos archipelago, the report added.
Many of these native people will now be found in several countries including Seychelles, Mauritius and the United Kingdom.
Following the ICJ ruling, the UN general assembly would now have to deal with the question of the resettlement of the Chagos Islanders who have been expelled. The ruling could also force Washington to negotiate with Mauritius over the future of the Diego Garcia base, according to analysts.
The majority decision by the court is, however, advisory, as the matter of who holds sovereignty over the Islands will now return to the United Nations General Assembly for debate.
The Assembly, in 2017, passed a resolution to refer the matter to the ICJ. Though several former colonial nations voted in support of sending the case to the ICJ, Germany, France, Canada, and other allies of the U.K. did not support.
Monday’s ruling, even though advisory, is seen as “a humiliating blow to Britain’s prestige on the world stage,” according to an analysis by The Guardian.
A Foreign Office spokesperson said: “This is an advisory opinion, not a judgment. Of course, we will look at the detail of it carefully. The defence facilities on the British Indian Ocean Territory help to protect people here in Britain and around the world from terrorist threats, organised crime and piracy.”
The Mauritian government, which has embraced the ruling, said it was a “historic moment in efforts to bring colonialism to an end and to promote human rights, self-determination and the international rule of law”.
Namira Negm, who represented the African Union in the court case, said: “The full decolonization of Mauritius, and of Africa, is long overdue.”
“The ICJ has made it clear that this must be accomplished today and not tomorrow. Only then the Africans can be free and the continent can aspire to live free of colonialism.”