May 22 (UPI) — A signing ceremony ceding the British Indian Ocean Territory of the Chagos Islands to Mauritius on Thursday was called off at the last moment after Britain’s High Court granted an injunction in the middle of the night to islanders opposing the deal.

“On-call” judge, Justice Goose, granted the temporary stay at 2:25 a.m. local time to two Chagos petitioners, ruling that the defendant, the Home Office, must “maintain the jurisdiction of the United Kingdom over the British Indian Ocean Territory until further order,” pending a further hearing during working hours Thursday.

The 11th-hour legal action forced the ceremony with Prime Minister Keir Starmer and Mauritian government representatives to be put on hold.

Stuart Lake, legal counsel for Beatrice Pompe, one of the claimants, told the Financial Times that his client was “deeply concerned that the government has chosen to give up sovereignty of the Chagos Islands without any consultation or protections for those that are indigenous to the islands.”

A British government spokesman declined to comment but insisted the deal with its former colony was “the right thing to protect the British people and our national security.”

Under the agreement, Britain will transfer sovereignty to Mauritius of the archipelago, home to a giant U.K.-U.S. military base on the island of Diego Garcia, but retain control of Diego Garcia by leasing it back on a 99-year, multi-billion dollar deal.

The United States pays Britain for use of the base, but the figure has never been made public.

Diego Garcia inhabitants have been engaged in a decades-long legal battle against their forcible displacement during the construction of the base throughout the late 1960s, mainly to Mauritius, the Seychelles and Britain, with the Chagos Islands split off from Mauritius when it became independent in 1968.

Joining a protest by Chagos people outside Parliament, the opposition Conservative Party’s shadow foreign secretary Priti Patel called Thursday’s legal intervention “a humiliation” for Starmer and Foreign Secretary David Lammy.

“Their rights, views and voices over the future of Chagos have been ignored by Labour which continues to cause distress and uncertainty for this wonderful community,” she wrote in a post on X.

“Labour’s Chagos Surrender Deal is bad for our defence and security interests, bad for British taxpayers and bad for British Chagossians,” said Patel.

The deal has also been condemned by Human Rights Watch, which has demanded Britain and the United States pay reparations after a 2023 report alleged the “forced displacement of the Chagossians and ongoing abuses amount to crimes against humanity committed by a colonial power against an Indigenous people.”

The United States initially welcomed the deal when it was struck in October and will see the other 57 currently uninhabited islands in the archipelago opened up for settlement. Diego Garcia, however, will remain out of bounds to its former residents and their descendants on “security grounds.”

U.S. President Joe Biden called the deal “a clear demonstration that through diplomacy and partnership, countries can overcome long-standing historical challenges to reach peaceful and mutually beneficial outcomes.”

But the deal was delayed after Donald Trump won back the presidency in November, pending his approval, and after the elections days later in Mauritius over the value of the lease.

Trump gave his backing in February during a visit to Washington by Starmer, despite warnings from Secretary of State Marco Rubio and other senior Republicans who said Mauritius’ links to China posed a “serious security threat” to U.S. national security.