Trump had urged Starmer to scrap the deal, despite earlier expressing support for the treaty. In January, the president described the plan as an “act of total weakness.”

UK government officials said they are not entirely abandoning the agreement—which would transfer sovereignty of the British territory to Mauritius—but have run out of time to pass the necessary legislation before Parliament is prorogued in the coming weeks. However, a new Chagos bill is not expected to feature in the King's Speech in mid-May.

It is understood that the UK has still not received a formal exchange of letters from the United States—a legal requirement for the treaty to be enacted. The Chagos Islands—officially known as the British Indian Ocean Territory—are located in the Indian Ocean, and Britain has controlled them since the early 19th century.

The deal would see the UK cede sovereignty of the territory to Mauritius and pay an average of 101 million pound (USD 136 million) a year to lease back a joint UK-US military base on the largest island, Diego Garcia. A government spokesperson said: “Diego Garcia is a key strategic military asset for both the UK and the US.

“Ensuring its long-term operational security is—and will continue to be—our priority. It is the entire reason for the deal. We continue to believe the agreement is the best way to protect the long-term future of the base, but we have always said we would only proceed if it has US support. We are continuing to engage with the US and Mauritius.”

The UK had been in the process of passing legislation to enshrine the Chagos deal into law. The bill was in the final stages of its passage, but officials say time has now run out. Simon McDonald, a former Foreign Office permanent secretary, told the BBC’s Radio 4 Today programme on Saturday that the government had “no other choice” but to shelve the deal.

“The UK had two objectives: one was to comply with international law, and the second was to reinforce the relationship with the United States,” he said. “When the president of the United States is openly hostile, the government has to rethink. So this agreement—this treaty—will go into a deep freeze for the time being.”

Asked whether the government could have made different choices earlier that would have allowed the plan to proceed, Lord McDonald said that once the issue went to the International Court of Justice, “we were bound by the outcome of this process.” In 2019, the court issued a non-legally binding opinion that the UK should end its control of the islands “as rapidly as possible.” (BBC)