Bertrice Pompe and Bernadette Dugasse walk, following a court injunction that temporarily blocked the UK from concluding Chagos Islands deal with Mauritius, outside the High Court in London, Britain, May 22, 2025. REUTERS/Suzanne Plunkett

By Muvija M and Michael Holden

LONDON (Reuters) -Britain can conclude a deal with Mauritius on the future of the Chagos Islands on Thursday after a judge at London's High Court overturned an eleventh-hour injunction which had blocked the agreement being signed earlier.

Lawyers representing a British national born in the Chagos Islands were granted an interim injunction in the early hours of Thursday morning, postponing the formal signing of the treaty which aims to secure the future of the strategically-important U.S.-UK Diego Garcia air base.

Bertrice Pompe and Bernadette Dugasse stand, following a court injunction that temporarily blocked the UK from concluding Chagos Islands deal with Mauritius, outside the High Court in London, Britain, May 22, 2025. REUTERS/Suzanne Plunkett

But Judge Martin Chamberlain lifted the injunction following a hearing later on Thursday, clearing the way for Britain to sign the multi-billion dollar deal to cede sovereignty of the Chagos Islands to Mauritius.

The deal, the details of which were first announced in October, would allow Britain to retain control of the strategically important base on Diego Garcia, the largest island of the archipelago in the Indian Ocean, under a 99-year lease.

An undated file photo shows Diego Garcia, the largest island in the Chagos archipelago, in the middle of the Indian Ocean. REUTERS/HO/U.S. Navy

Following the court's decision to overturn the injunction, the agreement is due to be signed off later.

James Eadie, the government's lawyer, said they needed a decision by 1200 GMT in order for the deal to be agreed on Thursday and "everyone is standing by".

He said the delay was damaging to British interests and "there is jeopardy to our international relations … (including with) our most important security and intelligence partner, the U.S."

The earlier injunction had been granted following action by Bertrice Pompe, a British national who was born in Diego Garcia and has criticised the deal for excluding Chagossians.

UK-based Chagos Islanders protest over the planned ceding of sovereignty of the islands by Britain to Mauritius, outside of the Houses of Parliament, in London, Britain, October 7, 2024. REUTERS/Toby Melville/File Photo

It was the latest legal action in the last two decades brought by members of the wider Chagossian diaspora, many of whom ended up in Britain after being forcibly removed from the Indian Ocean archipelago more than 50 years ago.

They have said they cannot endorse an agreement they were not consulted on, while critics have also said the deal plays into the hands of China, which has close trade ties with Mauritius.

In 1965 Britain detached the Chagos Islands from Mauritius - a former colony that became independent three years later - to create the British Indian Ocean Territory.

(Reporting by Muvija M, Michael Holden and Sam Tobin in London and Mike Stone in Washington; Editing by William Schomberg, Elizabeth Piper, Hugh Lawson and William James)