UK signs deal to hand over control of Chagos islands

The UK has signed a long-awaited deal to hand control of the Chagos Islands to Mauritius.

It means Britain will give up sovereignty of the Indian Ocean territory and lease back the vital UK-US Diego Garcia military base - at a cost of billions of pounds to the taxpayer.

Politics Live: Starmer signs deal to hand over UK control of Chagos Islands to Mauritius

In a news conference, Prime Minister Sir Keir Starmer said the base is of the "utmost significance to Britain", having been used to deploy aircraft to "defeat terrorists in Iraq and Afghanistan", and "anticipate threats in the Red Sea and the Indo-Pacific".

He said the base was under threat because of Mauritius's legal claim on the Chagos Islands, which has been recognised by multiple international courts.

"If we did not agree this deal, the legal situation would mean that we would not be able to prevent China or any other nation setting up their own bases on the outer islands, or carrying out joint exercises near our base," Sir Keir said.

"We would have to explain to you, the British people and to our allies, that we'd lost control of this vital asset.

"No responsible government could let that happen, so there's no alternative but to act in Britain's national interest by agreeing to this deal.

"We will never gamble with national security."

The deal means the UK will lease the base from the Mauritian government over 99 years.

Confusion over costs

Sir Keir said the average cost per year is £101m but the net overall cost is £3.4bn, not £10bn, and all public sector projects are measured in net costs.

However, there is confusion over the government's calculations as the full agreement between the UK and Mauritius reveals the UK will pay:

• £165m a year for the first three years;
• £120m for years four to 13;
• £120m plus inflation for every year after to year 99;
• £40m as a one-off to a fund for Chagossians;
• £45m a year for 25 years for Mauritian development.

If inflation were to remain zero for the next century, this would work out to around £10bn over 99 years.

Assuming an average of 2% inflation, Sky News analysis suggests costs could rise as high as £30bn.

Downing Street stood by its figures, saying government accounting principles were applied to adjust for long-term costs and the value of the pound today is worth more than the pound in the future.

Officials denied suggestions from journalists that was financial sophistry, insisting it was "standard practice".

Sir Keir said that had he not struck the deal today, Mauritius would have taken the UK to international courts and probably won, with extra penalties implemented.

However the Tories - who started negotiations in government - have branded the move a "surrender tax".

Sovereignty row

The Chagos Archipelago was separated from Mauritius by the UK in 1965, when Mauritius was a British colony.

Mauritius gained independence from the UK in 1968 and since then has been trying to claim the archipelago as Mauritian.

In the late 1960s, the US asked the UK to expel everyone from the archipelago so they could build a naval support facility on the largest island, Diego Garcia. It is leased to the US but operates as a joint UK-US base.

The UK has been under pressure to hand back control of the territory, after the UN and the International Court of Justice sided with Mauritius.

The treaty said the deal would "complete the process of decolonisation of Mauritius".

Tory leader Kemi Badenoch said that "surrendering" the Chagos Islands to Mauritius "is an act of national self-harm".

"It leaves us more exposed to China, and ignores the will of the Chagossian people. And we're paying billions to do so," she said.

Reform UK leader Nigel Farage echoed those comments, accusing Sir Keir of caring more about foreign courts "than Britain's national interest".

'Deal inherited from Tories'

However, Sir Keir said he "inherited a negotiation in which the principle of giving up UK sovereignty had already been conceded" by the Tories.

He said "all of the UK's allies" support the deal, including the US, NATO, Five Eyes and India, and that those who are against it include "Russia, China, Iran...and surprisingly, the leader of the opposition, and Nigel Farage".

Defence Secretary John Healey, who was also at the news conference, added that the last government failed to strike a deal despite 11 rounds of talks, leaving Labour to "pick up the challenge".

He said ministers "toughened the terms and the protections and the control that Britain can exercise through this treaty".

Under the deal's terms, a 24-nautical mile buffer zone will be put in place around the island where nothing can be built or placed without UK consent.

The UK will retain full operational control of Diego Garcia, including the electromagnetic spectrum satellite used for communications which counters hostile interference.

Marco Rubio, the US Secretary of State, said he welcomed the "historic agreement", saying it "secures the long-term, stable and effective operation of the joint US-UK military facility at Diego Garcia, which is critical to regional and global security".

"We value both parties' dedication. The US looks forward to our continued joint work to ensure the success of our shared operations," he said.

The agreement had been due to be signed on Thursday morning but was temporarily blocked by an injunction hours before. A High Court Judge subsequently discharged the injunction at midday.

(c) Sky News 2025: UK signs deal to hand over control of Chagos islands