Credit: NASA Johnson, CC BY-NC 2.0

The landmark agreement between the UK and Mauritian governments was signed yesterday despite last-minute legal trouble, including a late-night emergency injunction which was granted and overturned just a few hours later.

Two Chagossian women, Bernadette Dugasse and Bertrice Pompe, sought to block the deal because it would not allow them to return to their home island of Diego Garcia.

The UK, which currently administers the islands as the British Indian Ocean Territory (BIOT), expelled the Chagossian population in the 1960s and 1970s to make way for the base.

Historic documents show British officials disparaged the local population of at least 1,000 people as “some few Tarzans or Men Fridays” and massacred their pets during the mass deportation.

The International Court of Justice (ICJ) and the International Tribunal for the Law of the Sea (ITLS) have already ruled that the islands belong to Mauritius, having been illegally separated from the rest of the island country during the process of decolonisation.

The UK government, which has presented the deal exclusively in terms of national security, has said further international legal proceedings could have rendered the base “inoperable”.

It warned that provisional measures could have been imposed within weeks by an Arbitral Tribunal under the Law of the Sea Convention, affecting the ability of British military forces to patrol the waters around the base.

As well as a 99-year lease for the base at a cost of £101 million per year, the deal provides for a 24-nautical-mile buffer zone around the base where nothing can be built or placed without UK consent.

The UK will also have an effective veto on developments on the other islands, some of which are more than 100 nautical miles away from the base.

John Healey, the defence secretary, said: “As the world becomes more dangerous, our military base on Diego Garcia becomes more important. Today’s treaty secures full operational control, strengthens our UK-US defence partnership and keeps British people safe at home for the next 99 years and beyond.

“Without this base, our ability to deter terrorists, defend our interests and protect our troops around the world would be at risk. This agreement will safeguard our national and economic security for generations to come.

“Critically, the deal ensures the UK retains full operational control of Diego Garcia, including management of the electromagnetic spectrum satellite used for communications — vital for countering hostile interference.”

David Lammy, the foreign secretary, added: “This treaty secures the Diego Garcia military base for generations to come, protecting national and global security. 

“Without this deal, the land, sea and air operations of the base would become inoperable — doing nothing was not an option. 

“The US, Australia, Canada and India all back this deal because they understand its importance for global security. This government has always been clear that we will act in the national interest, not gamble with our national security like those who oppose this deal.”