By any objective measure, the case for handing the Chagos Islands to Mauritius is now in ruins.
What was once presented by Sir Keir Starmer’s Government as a sober, necessary security deal has unravelled into a treaty that is legally questionable, strategically reckless, environmentally dangerous, financially indefensible, and above all, unnecessary.
New evidence from the United States, mounting warnings from military chiefs, and a cascade of parliamentary and legal concerns have exposed a stark reality. There is no longer a credible reason to proceed with this transfer of sovereignty.
If this Bill goes through, it will not be because it is right. It will be because the Government chose stubbornness over facts.
1) It was not in Labour’s manifesto, in fact, it contradicts it
Labour stood for election in July 2024 promising to:
- Always defend British Overseas Territories’ sovereignty.
- Uphold their right to self determination.
The Diego Garcia and BIOT Bill does the opposite.
It transfers sovereignty over the Chagos Archipelago away from a British Overseas Territory. It does not provide the Chagossian people with a binding act of self determination. At best, it offers a non binding, uncertain process while sovereignty is ceded regardless.
There was no manifesto commitment to surrender Chagos. Quite the reverse. This Bill represents a direct breach of Labour’s own pledge.
2) The United Nations has told Britain to stop
In an extraordinary intervention, the UN Committee on the Elimination of Racial Discrimination has formally called on the UK to suspend ratification of the treaty.
This is not routine criticism. It is a rare and serious rebuke from a core body of the international human rights system.
The Government has ignored it. If Parliament presses ahead, it will not be respecting international law. It will be overruling it.
3) The Chagossians are being denied real self determination, again
The Bill changes the territorial status of the Chagos Islands without a credible, binding referendum that could block the transfer.
There is no clear mechanism to honour a no vote from the Chagossian people. Their fate is being decided for them, just as it was in the 1960s and 70s.
So alienated are the Chagossians that they have now established a Government in Exile, declaring it will stand until they receive a binding referendum on their homeland’s future.
4) A lawful, workable British alternative was ignored
A clear alternative existed:
Resettle Chagossians on their islands, excluding Diego Garcia.
Maintain BIOT as a self governing British Overseas Territory.
Preserve the US base with full operational freedom.
Avoid complications under the Pelindaba Treaty, since the UK is not a signatory.
This option would have protected sovereignty, rights, security and the environment. It was never seriously pursued. This needs to be revisited.
5) Resettlement under Mauritius is unrealistic
Mauritius is over 1,000 miles away and does not have a navy.
So incapable is it of projecting authority that both the UK and India have had to offer ships merely so Mauritian officials could raise their flag in Chagos.
A state that cannot even reach its own territory independently will struggle to support Chagossian resettlement, build infrastructure, maintain transport links or govern such a remote archipelago.
The promise of resettlement under Mauritius is, in practice, hollow.
6) Parliamentary scrutiny was curtailed
In the Commons, the Government attempted to compress Committee, Report and Third Reading into a single day, effectively neutering scrutiny of a treaty with generational consequences.
A cross party CRaG motion, signed by 107 MPs from six parties, seeking to block ratification, was denied debate.
This was not orderly lawmaking. It was a rush job.
7) The Third Reading in the Lords was highly irregular
At Third Reading, peers were asked four times whether they were content with the Government’s motion.
On at least the first three occasions, not content was clearly audible. A division should have been called.
Instead, the Deputy Speaker and Government Chief Whip intervened mid vote, sowing confusion. Conservative and Crossbench peers were wrongly told they were voting against their own motion.
No division ever took place.
This episode has damaged confidence in the integrity of the process.
8) Environmental catastrophe now looms
For more than 50 years, Britain has kept the Chagos Islands pristine.
Of the 60 islands, 59 are inhabited only by wildlife. The UK created and enforced one of the world’s most important Marine Protected Areas, safeguarding coral reefs, tuna stocks and extraordinary biodiversity.
Mauritius is over 1,000 miles away, lacking naval, financial and enforcement capacity, and already signalling openness to commercial fishing.
Labour’s own minister, Baroness Chapman, admitted in the Lords that Mauritius lacks the capability to protect the area.
A Mauritian Fisheries Minister has even said Mauritius could license trawlers to fish anywhere in the Chagos EEZ, proof that the risk of exploitation is real, not theoretical.
Once sovereignty is surrendered, environmental protection cannot be clawed back.
9) The Pelindaba Treaty poses a serious military risk
Mauritius is a signatory to the Pelindaba Treaty, which bans nuclear weapons on African territory.
Diego Garcia has long supported missions involving nuclear powered vessels and platforms vital to Western deterrence and power projection.
Even if current assurances are given, a future Mauritian government, or third parties, could use Pelindaba to challenge or constrain operations.
That risk does not exist under current British sovereignty.
10) Global security is weakened, not strengthened
The treaty would place 60 strategically vital islands under a state with no navy, leave the UK with only a right to object, not a veto, over developments on 59 islands, create a foreign sovereign landlord over a critical base, and introduce arbitration, long term payments and vulnerability to diplomatic pressure.
In an age of lawfare and geopolitical coercion, this is not diplomacy. It is strategic self harm.
Over 40 senior British figures have urged President Trump to block Starmer’s deal citing the global security risks including former Prime Ministers and Defence Ministers.
11) A dangerous precedent for other British territories
The Bill treats a non binding advisory opinion of the International Court of Justice as effectively determinative of British sovereignty.
If Parliament accepts this, it sets a precedent that could be weaponised against Gibraltar, the Falklands, Ascension, and Akrotiri and Dhekelia.
No British Overseas Territory would be safe.
12) Parliament’s authority is diminished
This Bill asks Parliament to accept that sovereignty can be surrendered, peoples ignored, international warnings dismissed, environmental stewardship abandoned and scrutiny curtailed.
If this stands, future governments will cite it again and again.
13) There is a live Judicial Review
A Judicial Review organised by the Great British PAC and fronted by the Chagossian people themselves was heard in October. Judgment has been delayed.
Parliament may complete this process before the court rules, effectively nullifying the Chagossians’ right to be consulted.
For many MPs, this is a serious rule of law issue.
14) Starmer’s central argument has collapsed
The Prime Minister’s key claim has been that the treaty is needed to secure the Diego Garcia base.
That argument is now untenable.
On 13 January 2026, the US Department of Defense awarded a 656 million dollar contract to Amentum Mitie Pacific for base operating support services at Diego Garcia, running to 2034.
This proves the US is planning a long term presence under existing arrangements, there is no imminent legal or operational crisis forcing a sovereignty transfer, and Diego Garcia is functioning, funded and strategically valued without the treaty.
In other words, the base is already secure.
Starmer’s final justification has evaporated.
15) The taxpayer faces a bill of up to £35 billion
The Government initially claimed the treaty would cost around £3.4bn.
The Government Actuary’s Department later suggested it could be closer to £34–35bn.
Payments are linked to UK inflation for 99 years, uncapped, unpredictable and legally binding.
At a time of strained public finances, this is fiscal recklessness.
16) Even Top Brass have warned it is dangerous
Retired admirals and generals, including former commanders with experience in the Indo Pacific, NATO and US UK operations, have warned that converting a sovereign base into a leased one under a third country introduces unacceptable strategic risk.
Their message is clear. Sovereignty matters for military freedom of action.
This treaty weakens, rather than strengthens, allied security.
Conclusion
Taken together, these are not minor objections.
They amount to a comprehensive failure of consent, legality, stewardship, scrutiny, financial responsibility and national security judgment.
There is now no credible security case for handing over the Chagos Islands. There is only political obstinacy.
Every MP should look at the evidence and vote this Bill down.
Britain should keep Chagos British.
By Claire Bullivant
Good article which sums up the key points rather well. It’s always worth reiterating that Mauritius has no valid claim to the islands. It has never owned the islands. It is a thousand miles from the islands. This has been a display of financially-motivated opportunism. Lack of support for the UK when the UN advisory opinion was given was largely down to 2 factors – cynical use of the word decolonisation and the UK’s isolation from the EU immediately post Brexit. The raising of the Mauritian flag and placement of a plaque declaring Mauritian sovereignty was an illegal act and was well documented by the BBC who were in attendance. The cleanup of this pristine natural area after they had left (they had plainly had a good time) took a fair bit of time and effort and was an indication of how much non-monetary value Mauritius would have for the world’s most important Marine Protected Area if the world allows them stewardship.
Why has the Pentagon awarded a $M656 contract over 7 years to Amentum Mitie Pacific to supply a space hub on Diego Garcia immediately after the House of Lords passed the third reading if they considered the long term security of the base was at risk if the deal were to go ahead?
However, I believe the reason why the Liz Truss government started negotiations with Mauritius in 2022 followed by Sunak and completed by Starmer in 2024 was that it closes the door to immigration by Sri Lankan Tamils. Over 50 Sri Lankan Tamils were held in tents for 3 years since 2021 next to the military base. A BIOT Court ruled that the UK government acted illegally in detaining them and in 2024 they were repatriated to the UK. By ceding sovereignty any migrants landing in the Chagos Archipelago including Diego Garcia will be a Mauritian problem, while both the UK and US keep the military base for 140 years.
Chagossians, however have been victimised and dispossessed since the 1960s. It is the valiant struggle of Olivier Bancoult who took the UK government to courts in the UK and European on numerous occasions to redress the wrongs. It was his fights in the courts since the 1990s that the British government finally in 2022 allowed Chagossians and their descendents stranded in the slums of Port Louis to apply for British Citizenship (BIOT) without having to pay for the application process fee for Citizenship which is in excess of £1,300 per applicant. Many could not afford this and those who could, left loved ones behind in the slums of Port Louis and families were separated, exacerbating their suffering. Since then, there have been an increasing number of Chagossians moving to the UK, with minimum support from the UK government for settlement. Since 2022, there has been an exponential increase of Chagossians applying for BIOT Citizenship and taking up residency in the UK, which will be terminated in 2027.
Let’s hope that the Mauritius will have the will and means to resettle those Chagossians who wish to live on their land of birth as soon as sovereignty reverts to the government in Port Louis. Many Chagossians have died in the slums of Port Louis, having lived in the hope that this day will come. The oldest Chagossians living in exiled is 98 years old, and the youngest born in the Chagos is 54 years old.
As for those Chagossians born in Mauritius and settled in the UK as BIOT citizen, you will always be Mauritian and UK dual citizens. Both nations have a duty of care for you. So the fight for justice is not over.