The Foreign Office has suggested the agreement to hand the Chagos Islands over to Mauritius is under review after previously presenting it as a done deal.

In a statement released today, the government department said both sides were keen to finalise a renewed treaty “as quickly as possible”.

It comes after the Mauritius’ prime minister Dr Navin Ramgoolam, who was elected after the agreement with the UK was reached, claimed the current terms “would not produce the benefits that the nation could expect” on Tuesday.

He said while he “is still willing to conclude an agreement” with the UK, it submitted counter-proposals so an agreement which is “in the best interest of Mauritius can be concluded”.

The strategically significant islands are based in the Indian Ocean and have a UK-US military base at Diego Garcia.

Labour announced in October that it was handing sovereignty of the islands over to Mauritius but would the military base would continue to operate as usual.

At the time, foreign secretary David Lammy said the move would “strengthen our role in safeguarding global security”.

News of the agreement was met with backlash from the Conservatives and Reform UK leader Nigel Farage, who called it an “act of surrender” which threatened the sovereignty over other overseas territories.

There are also concerns President-elect Donald Trump may try to block the deal because it would be handing over the archipelago to one of China’s allies.

After Ramgoolam’s remarks on Tuesday, Starmer’s official spokesman later told reporters: “We’ve always said we want to engage with the new administration in order to finalise the deal.

“I can’t go into the detail of the discussions, but our position is clear. We think the agreement protects the UK/US security at the base which was under threat and remains in both sides’ shared interests.”

Foreign office minister Stephen Doughty also said the new Mauritius PM had written to Starmer since getting into office to reaffirm his commitment to the deal.

But in a statement released on Friday, the Foreign Office said: “Mauritius and the UK have held a series of productive, ongoing conversations and exchanges on finalising a historic treaty on the exercise of sovereignty over the Chagos archipelago.

“Both countries reiterated their commitment to finalising a treaty as quickly as possible, whose terms will agree to ensure the long-term, secure and effective operation of the existing base on Diego Garcia and that Mauritius is sovereign over the archipelago.”

The Chagossians were kicked out of the central Indian Ocean land by 1973 so the military base in Diego Garcia could be built.

The International Court of Justice (ICJ) previously ruled the UK’s administration of the territory was “unlawful” and must end.