Chagos islanders have called for Yvette Cooper to scrap the Chagos deal just hours after she was appointed Foreign Secretary.
Ms Cooper was moved to the Foreign Secretary from the Home Secretary, replacing David Lammy, who has become Deputy Prime Minister and Justice Secretary.
Friends of the British Overseas Territories congratulated Ms Cooper on her appointment but immediately went on to demand that she "reset" the Chagos Islands Deal.
Its post on X read: "We call on you to scrap this deal, engage with the Chagossian community, and protect the UK national interest. Now is your chance to act."
The High Court ruled back in May that the Chagos deal can go ahead after an emergency injunction was put into place.
The deal sees Britain give up sovereignty of the island territory to Mauritius and lease back a crucial military base.
It was passed after Justice Chamberlain said the injunction should be discharged, after Bertrice Pompe, one of two British women born on the Chagos Islands, was granted an injunction at 2.25am against the Foreign, Commonwealth and Development Office for "interim relief".
He said: "I have concluded that the stay granted by Mr Justice Goose should be discharged and there should be no further interim relief."
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Yvette Cooper was moved to the Foreign Secretary from the Home Secretary
| PAA Government spokesman welcomed the ruling at the time, saying the agreement was "vital to protect the British people and our national security".
Shadow foreign secretary Dame Priti Patel criticised the High Court's "decision," saying: "This will be very disappointing for Chagossians".
She continued: "They deserve great credit for the dignified way they have fought and campaigned for their rights. But this process has once again highlighted the shameful actions of Labour ministers.
"They have ignored them and are disgracefully forcing through the surrender of the sovereignty of the Chagos Islands and handing over billions of pounds of taxpayers' money to Mauritius."
She said the Chagossians have "been betrayed by Labour and their cowardly actions".
Campaigner Misley Mandarian previously told Sky News: "We've been fighting more than 50 years. Like I said earlier, no retreat, no surrender.
"We will fight to the end. Keir Starmer has got a fight - the Chagossians are very aware of it.
"And we will never, never let an island - a British island - go to Mauritius."
Hundreds of Chagos Islanders have pushed the Government to reverse its deal
| GETTYYvette Cooper was moved to the Foreign Secretary from the Home Secretary after 14 months in the role.
Under her tenure, over 50,000 small boat migrants arrived in the UK illegally, with 500 more today on the first day of Shabana Mahmood's lead.
Ms Cooper secured a deal with France to transfer migrants back from the UK, in a "one-in, one-out deal".
Sir Keir Starmer said the deal "sends a clear message - if you come here illegally on a small boat you will face being sent back to France".