The Biggar Picture

The Biggar Picture

Chagos

The war has not yet been lost.

Nigel Biggar's avatar
Nigel Biggar
Jan 12, 2026
∙ Paid

I arrived home late last Monday night, having spent the second half of the day in the House of Lords attending the Report stage of the bill to ratify the treaty whereby the UK surrenders to Mauritius sovereignty over the Chagos Islands—including the military base on Diego Garcia—in return for a ninety-nine-year lease.

For readers who missed—or have forgotten—my post on this topic on August 6th, let me rehearse my view. Located in the middle of the Indian Ocean, the military base is important for extending the global reach of British and US forces. At first glance, exchanging sovereignty for a lease looks like a very poor deal, making possession of the strategic base less secure at a time of growing international tensions.

The Biggar Picture is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

So why has Keir Starmer’s government signed up to a treaty that does just that?

The treaty presents itself upfront as correcting the injustice done when 1,700 Chagossians were forced to leave their homes on Diego Garcia between 1967 and 1973, to make way for the military base. In the preamble, the two governments “recognis[e] the wrongs of the past” and declare themselves “committed to supporting the welfare of all Chagossians”. Yet the process that produced the treaty does not bear this out. The Chagossians themselves were barely consulted, probably because it is known that many strongly resist subjection to Mauritian rule.

Diego Garcia

Moreover, the treaty binds the Mauritian government to do little for them. Oddly, Article 6 declares that Mauritius is “free” to implement a programme of resettlement. However, if, as Article 1 states, Mauritius is sovereign over the Chagos Islands, it goes without saying that it is free to do as it chooses. It does not need stating. So, the effect of stating it is to highlight the fact that Mauritius has refused any obligation to resettle the islanders.

Article 11 commits the UK to provide capital of £40 million to create a trust fund for the islanders, but it leaves the Mauritian government entirely at liberty to choose how to use it. Yet, when it received £650,000 (equivalent to £7.7 million today) from the UK to compensate displaced islanders in 1972, it withheld the money for six years in punitive retaliation for Chagossian protests. And, again, nine years after it was given £40 million in 2016, to improve Chagossian welfare, it has only disbursed £1.3 million under restrictive conditions.

The treaty’s main concern lies elsewhere. As the preamble also says, it is “mindful of the need to complete the process of the decolonisation” of Mauritius. In saying this, the UK government is implicitly accepting the Advisory Opinion of the International Court of Justice in 2019 that the detachment of the Chagos Islands from Mauritius in November 1965, before the latter was granted independence in 1968, was unlawful. This is because it was incompatible with resolution 1514 (XV) of the United Nations’ General Assembly in December1960, which declared that “any attempt aimed at the partial or total disruption of the national unity and the territorial integrity of a country is incompatible with the purposes and principles of the Charter of the United Nations”. Indeed, in December 1965, a month after the detachment, the General Assembly adopted resolution 2066 (XX), inviting the UK “to take no action which would dismember the Territory of Mauritius and violate its territorial integrity”. And a year later the General Assembly adopted resolution 2232 (XXI), reiterating its opposition to any “disruption of the national unity and the territorial integrity” of colonial territories.

None of these resolutions makes good sense. The original, 1960 one was championed by the Irish ambassador to the UN, Frederick Boland, who was then President of the General Assembly. In promoting resolution 1514 (XV), he invoked Ireland’s loss of its “historic integrity” as a prime example of the injustice to be avoided. In so doing, he expressed the Irish nationalist’s typical historical blindness. The island of Ireland had never been a political unit apart from its union with Great Britain, and there is no natural law prescribing that a geographical integrity should be a political integrity. On the contrary, there can be very good reasons for dividing it. The reason that Ireland was divided in 1922 was because republican Irish people wanted home rule so much that they were prepared to take up arms to acquire it, while unionist Irish people detested it so much that they were prepared to take up arms to oppose it. Ireland was partitioned to prevent further civil war—a justified act of political prudence.

The 1965 and 1966 resolutions are no more sensible. The first talks luridly of ‘dismemberment’ as if the separation of parts of a colony must be the tearing apart of a natural organism, and of ‘violation’ as if some natural, moral law were being assaulted. But there is nothing natural about a political entity and there is no moral law against partition as such.

The 1966 resolution appeals to the “national unity” of Mauritius, as if the Chagos Islands weren’t separated by over a thousand miles of Indian Ocean and as if the islanders were an integral part of the Mauritian people. But many Chagossians feel as Mauritian as Irish republicans feel British. The only connection between Mauritius and the Chagos Islands is an accident of colonial, administrative convenience. Talk of some ‘national unity’ that was ruptured in 1965 is a romantic fiction. Besides, in 1965 the Mauritians agreed to the separation in return for £3 million (worth £74 million today) and the reversion of the islands when no longer needed for defence purposes.

Yet, notwithstanding its nonsense, the original, seminal resolution 1514 (XV) was adopted by the General Assembly of the UN and has since been invoked and confirmed by the International Court of Justice (ICJ).

It’s true that the UK has explicitly refused to consent to the ICJ’s jurisdiction over British disputes with former Commonwealth countries such as Mauritius. However, in its 2019 Advisory Opinion, the court positioned itself formally, not as adjudicating between two sovereign states’ conflicting claims, but as responding to a question from the UN’s General Assembly as to whether the UK had violated international law on the decolonisation of Mauritius in the 1960s. Notwithstanding the fact that that is a crucial point of current contention between the two countries, the ICJ presumed to find in Mauritius’ favour. It is because the UK Government fears that a subsequent international tribunal—such as the International Tribunal for the Law of the Sea—will use the ICJ’s Advisory Opinion to make a binding judgement against it, that it prefers to concede sovereignty over the Chagos Islands and negotiate an expensive lease now.

But there is more to the Government’s motivation than fear. In his October 2024 Bingham Lecture, the Prime Minister’s Attorney General, Lord Hermer, declared that Britain must champion respect for international law, so as to dispel the view in the ‘Global South’ that the international rules-based order and human rights are “imperialist constructs”. In other words, by surrendering its claim to sovereignty over the Chagos Islands, Britain will ‘decolonise’ itself and thereby win diplomatic capital. As the Labour peer, Lord Boateng, opined: “We can welcome this treaty as an end to a period of colonial rule”. This is what lies behind that other statement in the preamble to the treaty: that the parties desire “to build a close and enduring bilateral partnership based on mutual respect and trust”.

Lord Hermer

Yet the international law to which Lord Hermer would have the UK submit comprises the imprudent nonsense of UNGA’s resolutions 1514 (XV), 2066 (XX), and 2232 (XXI) and the Advisory Opinion of a court that, arguably, has exceeded its authority. It may be law, but it is bad law that serves to bring the international order into disrepute and damage its authority. So, for the sake of restoring confidence in international law, the UK should stand its ground, arguing the strong, rational case for its sovereignty over the Chagos Islands, exposing the romantic imprudence of the General Assembly’s resolutions, and reminding the international community that neither the ICJ nor ITLOS have jurisdiction. And if ITLOS were unwise enough to issue a binding judgment against the UK on the basis of the ICJ’s Advisory Opinion, the UK should, with respect, refuse to comply.

No doubt that would cost us diplomatic good will in ‘progressive’ quarters entranced by an idealised view of international law. But we have no good will to lose with ideologically hostile states such as China, Russia, and Iran. And the rest of so-called ‘Global South’ is not a politically uniform bloc. It embraces nations ranging from India to Nigeria and Peru, which have divergent—sometimes strongly opposing—interests and views. They would not all react with equal disapproval to principled non-compliance. Some might even be impressed by a self-confident Britain’s refusal to yield to cynical lawfare, in bold defence of the law’s integrity.

For all those reasons, then, I do not think that the treaty between the UK and Mauritius to transfer sovereignty over the Chagos Islands makes good sense—legally, morally, or in terms of Britain’s national interest—and I would like to see its ratification fail.

That is why, although I got home late on Monday night, I did so nonetheless with a moderate spring in my step. For in the course of the afternoon and evening, the Conservative Opposition—with the aid of my vote—had inflicted a series of significant defeats on the Government.

User's avatar

Continue reading this post for free, courtesy of Nigel Biggar.

Or purchase a paid subscription.
© 2026 Nigel Biggar · Privacy ∙ Terms ∙ Collection notice
Start your SubstackGet the app
Substack is the home for great culture