How Brexit helped Britain lose the Chagos Islands

LONDON — It was not the happy anniversary Brexiteers had hoped for.

On June 22, 2017, almost a year to the day after Britain voted to leave the European Union, representatives from 193 nations filed into the United Nations General Assembly Hall in New York to discuss another matter concerning the U.K.

The issue: Should the U.N. request an advisory opinion from its disputes court on the incendiary issue of one of Britain’s final imperial treasures: the Chagos Islands in the Indian Ocean.

Did the U.K. act unlawfully by separating the islands from Mauritius as part of British decolonization efforts way back in 1967? And had it breached international law when it forcibly prevented Mauritius from resettling Chagossians on the islands to make way for a U.S. military base?

The assembly’s verdict — a resounding yes — would set in motion a chain of events that culminated in the U.K. government’s controversial decision this October to hand the Chagos Islands back to Mauritius in a deal widely criticized by conservatives back home.

So what really happened behind the scenes?

The fact that the bilateral dispute had made it to the U.N. in the first place raised eyebrows among members of the U.K. delegation at the time.

“We do not doubt the right of the General Assembly to ask the [International Court of Justice] for an advisory opinion — on any legal question,” Matthew Rycroft, the U.K.’s then-representative to the U.N., told diplomats assembled in the hall in 2017.

“But the fact that the General Assembly has not concerned itself with this matter for decades shows that today’s debate has been called for other reasons.”

When the speeches were over, 94 countries voted in favor of a referral to the ICJ and just 15 against.

Out of the EU countries present, only Croatia and Hungary voted against while Cyprus voted in favor of the resolution. The other EU members abstained.

‘Brexit dropped from the heavens’

Many at the time saw the refusal of key EU countries to back Britain as a sign of the country’s diminished foreign influence after Brexit.

The country’s diplomatic efforts were spearheaded at the time by its gaffe-prone foreign secretary, and staunch Brexiteer, Boris Johnson.

“Brexit dropped from the heavens, quite frankly,” Philippe Sands, a legal adviser to Mauritius in the Chagos case, told POLITICO. “There is no question that, but for Brexit and Boris Johnson, the resolution would have had less chance of reaching the General Assembly, or being adopted with such a large majority.”

A spokesperson for Johnson dismissed that claim as “total rubbish.”

But Sands believes that, had the U.K. remained in the EU, the rest of the bloc would have supported it — and urged its allies to do the same.

This was also a view held inside the British government, according to a former civil servant at the Foreign Office, who was granted anonymity in order to speak frankly.

“It was widely viewed at the time in the Foreign Office that all EU countries and their allies ordinarily vote down such a motion affecting another member state at the General Assembly,” they said. “But post-Brexit we lost that protection, so the U.K. didn’t benefit from the EU votes and those of its allies, and hence the wheels being set in motion to Chagos leaving today.”

“In a way this is the first element of Brexit leading to the U.K. losing territory. It showed how that initial grab for purported sovereignty might actually lead to its diminution.”

As legal counsel to Mauritius, Sands had spent the days leading up to the vote lobbying other U.N. members in 10-minute slots. “It was plain that Britain’s stock had fallen, and the country was more isolated,” he said.

Although the mood music appeared to be in Mauritius’ favor, Sands — who writes about the issue in his memoir, the Last Colony — couldn’t quite believe what he was seeing when he watched the vote live on U.N. TV back in the U.K. 

“The Mauritian team was tiny — it was just three or four people against the might of the British and Americans, who were lobbying massively. We sensed it was going well, but we couldn’t believe it would actually happen, when push came to shove, until the actual vote.”

‘Rock-solid support’ pre-Brexit

David Hannay, the U.K.’s former ambassador to the U.N. and a crossbench peer, also noted a stark contrast between the support the U.K. could bank on before and after Brexit.

Before the U.K. voted to leave, Britain enjoyed “pretty rock-solid support at the U.N.” and there was a “working assumption that the EU stands by its members’ definition of their sovereignty and territorial integrity,” he said.

When Britain left the bloc, EU members “deserted that point, and their desertion carried with them a lot of others who might have stuck by it,” Hannay added, pointing out that “the French obviously were influential at that stage with a lot of African countries.”

A few months after the General Assembly vote, however, the U.K. suffered another blow when it lost its seat on the ICJ to India. This meant the court would be without a U.K. judge for the first time since its creation in 1946. Sands believes this was no coincidence. 

“The reality seems to be that Brexit, [the 2003 invasion of] Iraq and Chagos combined to cause the British to lose their judge,” he said. This was not on account of “poor lobbying” to secure the U.K. a spot, as some have said, but “poor political decisions” at home, Sands argues.

In 2019, the ICJ determined in an advisory opinion that the U.K.’s continued administration of the Chagos Islands “constitutes a wrongful act entailing the international responsibility of that State.” It said the U.K. “has an obligation to bring to an end its administration of the Chagos Archipelago as rapidly as possible, and that all Member States must cooperate with the United Nations to complete the decolonization of Mauritius.” 

Hannay points out that while a British judge on the ICJ is “in no sense obligated to support a U.K. view, the absence of such a person must have weakened the arguments that might have been heard at the ICJ when they took the General Assembly request for an advisory opinion.”

The U.K. then suffered yet another humiliating defeat at the U.N. when the General Assembly voted to accept the ICJ’s opinion, with only four countries supporting the U.K. and the U.S. in voting against — and 116 voting in favor. 

“You could sense the power slipping away,” recalled Sands. 

Resistance

At that point, the U.K. government chose not to comply with the ICJ’s ruling — something critics of the current Labour government’s deal argue it should have continued to do.

But the U.N. continued to apply pressure, and in 2021 its special international maritime court rejected the U.K.’s claim to sovereignty. The U.K.’s then-Conservative government agreed to reopen negotiations with Mauritius in 2022.

Finally, following years of negotiations, the Labour administration announced on Oct. 3 that — after more than half a century — it would give up sovereignty of the Chagos Islands to Mauritius, albeit with carve-outs to protect the U.K./U.S. airbase on Diego Garcia.

Looking back, Sands sees Britain’s EU departure as a major contributor. “Brexit was a handmaiden to the 2017 vote at the U.N., and without the decision to have a vote and then the vote itself, there wouldn’t have been an ICJ ruling,” he says. “So it is perfectly logical to say that Brexit contributed to this point.”

But Richard Gowan, U.N. director of the International Crisis Group, believes the U.K. would have lost the vote even if the EU had united behind it.

“The General Assembly is a venue where non-Western countries have a built-in majority, and sorting out the unfinished business of decolonization is a perennial priority,” he says.

“I think it is also true to say that the U.K. had not focused very much on the General Assembly in the years before 2017, as its focus at the U.N. was the Security Council,” Gowan adds. “After its set-backs in 2017, the U.K. mission in New York rebooted its approach to the General Assembly, and invested more in diplomacy there. I think Brexit may have been a factor, but it was not the only factor.”

Samuel Jarvis, a senior lecturer in international relations at York St John University, who has co-authored a paper on the U.K.’s declining influence at the U.N. post-Brexit, also believes the matter isn’t quite so clear-cut.

“What we found very clearly and definitively is that, regardless of whether the U.K. had left or remained in the European Union, they would have lost that [2017] vote,” he says. “The General Assembly is made up of lots more states from the global south which are much more sympathetic to a decolonization argument, which was what was put forward. So it was always the case that the U.K. would lose that vote, even if it had the full support of the EU. But that’s not to say that there weren’t other significant dynamics to the vote.”

Jarvis concedes that Brexit meant the U.K. won less support from its former EU colleagues than it would have had previously. But while decolonization is traditionally a divisive issue among EU-member states, Jarvis says “you would expect more support than the U.K. got,” especially among countries like France with a long colonial history.

But Brexit played another role in Britain’s ultimate decision to give up the islands, he believes.

As a result of Brexit, he said, “the U.K. needs to build closer relationships with states beyond Europe. If the U.K. wants to be a power that has stronger connections beyond Europe, it inevitably [needs] to better engage with Asia, South America and Africa in particular.

“If the U.K. is seeking to build stronger diplomatic ties with these states, then it is much harder if it is seen to be breaking international law, particularly on an issue linked to decolonization. And how can the U.K. effectively challenge states such as China on certain legal issues, if it is also seen to be violating international law in this way?”

‘Dismal act of self-harm’

Euroskeptics hotly contest the idea that Brexit Britain alienated its allies to the point of losing prized territory — and some reject Labour’s deal outright.

“The Chagos vote was the result of massive Chinese lobbying in the U.N. in which they played on general anti-colonial sentiment,” a spokesperson for Johnson said in a statement.

“The vote only took place because the Foreign Office mistakenly decided long before Brexit to engage with the legal process — though the claim of Mauritius was totally without merit.”

The spokesperson added: “Even after that vote there was no need for Britain to give up the islands. Had Boris Johnson and the Conservatives remained in power this dismal act of self-harm would quite simply never have happened.

“There is one reason and one reason only for the surrender of the Chagos islands — and that is the total spinelessness of Keir Starmer and his empire-hating Labour Party.”

MP Rupert Lowe, representing Brexiteer Nigel Farage’s Reform UK party, rejected Foreign Secretary David Lammy’s claim that a binding judgment from the ICJ against the U.K. “seemed inevitable.”

“That seems misleading verbal baby food at best,” he told the House of Commons. “So far, there has been a non-binding advisory opinion and nothing to suggest that we will breach any form of international law. At a time of increasing global conflict, will the foreign secretary explain to the House why there is such urgency to do what he is proposing? It seems to be a case of acting in haste and repenting at leisure.”

Some now fear the surrender of the islands could have dangerous knock-on effects for U.K. security. “We have no clear details of any safeguards that will guard against China, a close ally of Mauritius, setting up military facilities and surveillance capacity not far away,” Shadow Foreign Secretary Andrew Mitchell said in the same Commons debate.

‘In the right place’

While debate rages in London, Hannay, the former U.K. ambassador, is ultimately supportive of the outcome Britain has landed on. “I think we’re probably in the right place where we should have been anyway,” he said. “I don’t think anybody any longer disputes that the removal of the Chagossians way back by the government was quite wrong, unjustified and contrary to human rights.”

Sands spent years arguing for Mauritian sovereignty to be recognized under international law, and for the Chagossians to be able return to their lost homeland.

As an ardent Remainer, there’s an irony for him in the way Brexit played a part.

“It doesn’t make me feel any better about Brexit,” he said. “I regret it, but we are where we are, and we live with the consequences of what the people voted for.”