PRIME Minister Sir Keir Starmer faces calls to suspend his deal handing the Chagos Islands back to Mauritius after UN experts criticised its treatment of the Chagossian people.

The deal, agreed last month after long-running negotiations, returns sovereignty of the islands to Mauritius, but will see Britain lease back a military base on Diego Garcia, the largest of the islands.

But a panel of experts appointed by the UN Human Rights Council said retaining the base and continuing to bar Chagossians from Diego Garcia “appears to be at variance with the Chagossians’ right to return.”

The Chagossians were expelled from the islands between 1965 and 1973 to make way for the joint UK-US base and have not been allowed to return.

Although the deal includes a £40 million trust fund for the benefit of the Chagossians, the UN experts expressed concern that this would not provide an “effective remedy” for the islanders.

They also criticised an apparent lack of consultation of the islanders prior to the deal, saying: “We are gravely concerned about the lack of meaningful participation of Chagossians in processes that have led to the agreement.”

The experts added: “In light of these significant concerns, we call for the ratification of the agreement to be suspended and for a new agreement to be negotiated that fully guarantees the rights of the Chagossian people to return to all islands of the Chagos Archipelago, including Diego Garcia.”

But Mauritius’s chief legal adviser Philippe Sands KC told peers yesterday that former residents of the Chagos Islands were consulted on the deal.

Mr Sands, who has represented Mauritius in its legal battle with Britain since 2010, told a House of Lords committee he wanted to “knock on the head this idea that all of the Chagossians were not involved” in negotiations over the deal.

A spokesperson for the Foreign, Commonwealth and Development Office said: “The negotiations were between the UK and Mauritius with our priority being to secure the full operation of the base on Diego Garcia, and the deal has been welcomed by international organisations including the UN secretary general, African Union and Commonwealth.

“We recognise the importance of the islands to Chagossians and have worked to ensure the agreement reflects this.”