What is the Chagos deal? What is going on as court puts last-minute block from UK transferring Islands to Mauritius - who signed injunction?

The judge blocked the deal hours before it was expected to be signed off. The deal would see Britain give up sovereignty of the island territory to Mauritius and lease back a crucial military base there.

Downing Street insists it is the “right thing” but would not comment on the legal case. A hearing is expected to take place at 10.30am.

Mr Justice Goose granted an injunction at 2.25am against the Foreign Office for “interim relief” to Bertrice Pompe, one of two British women born on the Chagos Islands who had previously taken legal action over the deal. He said in his order: “The defendant shall take no conclusive or legally binding step to conclude its negotiations concerning the possible transfer of the British Indian Ocean Territory, also known as the Chagos Archipelago, to a foreign government or bind itself as to the particular terms of any such transfer”.

Prime Minister Keir Starmer had been expected to attend a virtual ceremony alongside representatives from the Mauritian government on Thursday morning to sign off on the deal after several weeks in which it appeared to be on hold over political difficulties. Under the injunction, the Government is required to “maintain the jurisdiction of the United Kingdom over the British Indian Ocean Territory until further order”.

The judge granted the injunction after considering an out of hours application from Ms Pompe and after reading a response from the Foreign Secretary and Prime Minister’s office. Bertrice Pompe, who initiated the emergency legal challenge, argued that the treaty would cause irreparable harm and violate fundamental legal and human rights principles.

She is a Chagossian, born on Diego Garcia and expelled at six months old. She grew up in the Seychelles and now lives in London. A British national, Ms Pompe—like thousands of Chagossians from the Seychelles and elsewhere—claims that she stands to gain nothing from the deal with Mauritius unless she applies for Mauritian citizenship.

A Government spokesperson said: “We do not comment on ongoing legal cases. This deal is the right thing to protect the British people and our national security.”

Senior Tory Robert Jenrick said the Chagos deal is a “bad deal” after a court injunction blocked it from being signed. The shadow justice secretary told Sky News: “It’s a sell-out for British interests.

“You’re seeing British sovereign territory being given away to an ally of China, and billions of pounds of British taxpayers’ money being spent for the privilege. This was always a bad deal.

“Keir Starmer did it because of his view of international law, where he wanted to put a non-binding judgment by a foreign court above the interests, the core security interests of the British people. And so if this group can force the Government to think twice, then all power to them.”