This morning, the UK missed/ignored a 6 month deadline given by the UN to hand over control of the Chagos Islands to Mauritius. The Mauritians say that they were forced to sell the islands in 1965 in return for independence, which was gained in 1969, while the response from the Foreign and Commonwealth Office in the UK is that Britain has had sovereignty over the islands since 1814.

How true is this claim? What is the history here? What are the consequences of ignoring a UN resolution?

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    It should be pointed out that the UK, as a permanent member of the security council and therefore with a veto, is quite different to any member which does not enjoy that privilege (or has a close ally which does). So any consequences for the UK could be very different compared to how it would be if the situation were reversed and it was Mauritius ignoring the resolution. Commented Nov 22, 2019 at 8:30
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    It's probably also worth pointing out that the entire place is a US military base, and honestly if anyone can make sense of why the UK still makes the place its problem that'd be really useful.
    – Jontia
    Commented Nov 22, 2019 at 8:47
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    Note that the decisions of both the UN General Assembly and the International Court of Justice are advisory, and so not binding. Nonetheless, this does not lessen the political pressure on the UK. Commented Nov 22, 2019 at 10:16
  • Wikipedia makes the history fairly clear.
    – user19831
    Commented Nov 22, 2019 at 10:28
  • @Jontia that could be a separate question, I think. Seeing how long the situation has been this way and seeing the controversy, it's probably a question some in the UK and internationally will have looked into.
    – JJJ
    Commented Nov 23, 2019 at 1:38

2 Answers 2


The BBC has an analysis article on the Chagos Islands dispute, from which I'll quote a few excerpts in an attempt to address your questions.

How true is this claim?

It's disputed. The UK says it's it's in the right, quoting from the article:

Britain's Foreign and Commonwealth Office (FCO) insists it has every right to hold onto the islands - one of which, Diego Garcia, is home to a US military airbase.

"The UK has no doubt as to our sovereignty over the British Indian Ocean Territory (BIOT), which has been under continuous British sovereignty since 1814," it said in a statement.

"Mauritius has never held sovereignty over the BIOT and the UK does not recognise its claim."

This claim is disputed by some in the UK, for example opposition leader Jeremy Corbyn, again quoting from the article:

But Labour Party leader Jeremy Corbyn said it was important to return the islands "as a symbol of the way in which we wish to behave in international law".

He added: "I am looking forward to being in government to right one of the wrongs of history."

Mauritius disputes this as well, and many members of the UN General assembly sided with Mauritius. Again, quoting from the Article:

The Chagos Archipelago was separated from Mauritius in 1965, when Mauritius was still a British colony. Britain purchased it for £3m - creating the BIOT.

Mauritius claims it was forced to give it up in exchange for independence, which it gained in 1968.

In May, the UN General Assembly voted overwhelmingly in favour of the Chagos Islands being returned - with 116 states backing the move and only six against.

The UN said that the decolonisation of Mauritius "was not conducted in a manner consistent with the right to self-determination" and that therefore the "continued administration... constitutes a wrongful act".

This follows after an International Court of Justice ruling earlier in 2019. From a previous article by the BBC reporting on that:

The International Court of Justice said the islands were not lawfully separated from the former colony of Mauritius.

And further in the article, the ruling is elaborated:

Judge Abdulqawi Ahmed Yusuf described the UK's administration of the Chagos Islands - located more than 2,000 miles off the east coast of Africa - as "an unlawful act of continuing character".

He added the UK was "under an obligation to bring an end to its administration of the Chagos Archipelago as rapidly as possible".

The advisory opinion by the International Court of Justice is very long. It considers a lot of evidence but it seems to be based, at least in my reading as a non-lawyer, around the principle of self-determination. The term self-determination appears 57 times in the advisory opinion. I will cite the last mention of self-determination in the ruling:

  1. Since respect for the right to self-determination is an obligation erga omnes, all States have a legal interest in protecting that right (see East Timor (Portugal v. Australia), Judgment, I.C.J. Reports 1995, p. 102, para. 29; see also Barcelona Traction, Light and Power Company, Limited (Belgium v. Spain), Second Phase, Judgment, I.C.J. Reports 1970, p. 32, para. 33). The Court considers that, while it is for the General Assembly to pronounce on the modalities required to ensure the completion of the decolonization of Mauritius, all Member States must co-operate with the United Nations to put those modalities into effect. As recalled in the Declaration on the Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations “Every State has the duty to promote, through joint and separate action, realization of the principle of equal rights and self-determination of peoples, in accordance with the provisions of the Charter, and to render assistance to the United Nations in carrying out the responsibilities entrusted to it by the Charter regarding the implementation of the principle” (General Assembly resolution 2625 (XXV)).

What is the history here?

The history is explained thoroughly in the advisory opinion by the International Court of Justice (I only quote points I think are relevant; the list of historic facts goes on for quite a while, I suggest reading it in the PDF if you're interested):

  1. Between 1814 and 1965, the Chagos Archipelago was administered by the United Kingdom as a dependency of the colony of Mauritius. From as early as 1826, the islands of the Chagos Archipelago were listed by Governor Lowry-Cole as dependencies of Mauritius. The islands were also described in several ordinances, including those made by Governors of Mauritius in 1852 and 1872, as dependencies of Mauritius. The Mauritius Constitution Order of 26 February 1964 (hereinafter the “1964 Mauritius Constitution Order”), promulgated by the United Kingdom Government, defined the colony of Mauritius in section 90 (1) as “the island of Mauritius and the Dependencies of Mauritius”.

  2. In accordance with General Assembly resolution 66 (I) of 14 December 1946, the United Kingdom as the administering Power regularly transmitted information to the General Assembly under Article 73 (e) of the Charter of the United Nations concerning Mauritius as a nonself-governing territory. The information submitted by the United Kingdom was included in several reports of the Fourth Committee (Special Political and Decolonization Committee) of the General Assembly. In many of these reports, the islands of the Chagos Archipelago, and sometimes the Chagos Archipelago itself, are referred to as dependencies of Mauritius. In its 1947 Report, Mauritius is described as comprising the island of Mauritius and its dependencies among which are mentioned the island of Rodriguez and the Oil Islands group of which the principal island is Diego Garcia. The Report of 1948 collectively referred to all of the islands as “Mauritius”. The Report of 1949 states that “there are dependent upon Mauritius a number of islands scattered over the Indian Ocean, of which the most important is Rodriguez . . . Other dependencies are: Chagos Archipelago . . . Agalega and Cargados Charajos”.

  1. In February 1964, discussions commenced between the United States of America (hereinafter the “United States”) and the United Kingdom regarding the use by the United States of certain British-owned islands in the Indian Ocean. The United States expressed an interest in establishing military facilities on the island of Diego Garcia.

  2. On 29 June 1964, the United Kingdom also commenced talks with the Premier of the colony of Mauritius regarding the detachment of the Chagos Archipelago from Mauritius. At Lancaster House, talks between representatives of the colony of Mauritius and the United Kingdom Government led to the conclusion on 23 September 1965 of an agreement (hereinafter the “Lancaster House agreement”, described in more detail in paragraph 108 below).

  3. On 8 November 1965, by the British Indian Ocean Territory Order 1965, the United Kingdom established a new colony known as the British Indian Ocean Territory (hereinafter the “BIOT”) consisting of the Chagos Archipelago, detached from Mauritius, and the Aldabra, Farquhar and Desroches islands, detached from Seychelles.

  4. On 16 December 1965, the General Assembly adopted resolution 2066 (XX) on the “Question of Mauritius”, in which it expressed deep concern about the detachment of certain islands from the territory of Mauritius for the purpose of establishing a military base and invited the “administering Power to take no action which would dismember the Territory of Mauritius and violate its territorial integrity”.

  5. On 20 December 1966, the General Assembly adopted resolution 2232 (XXI) on a number of territories including Mauritius. The resolution reiterated that

    “any attempt aimed at the partial or total disruption of the national unity and the territorial integrity of colonial Territories and the establishment of military bases and installations in these Territories is incompatible with the purposes and principles of the Charter of the United Nations and of General Assembly resolution 1514 (XV)”.

  1. Based on the 1966 Agreement, the United States and the United Kingdom agreed that the Government of the United Kingdom would take any “administrative measures” necessary to ensure that their defence needs were met. The Agreed Minute provided that, among the administrative measures to be taken, was “resettling any inhabitants” of the islands. The inhabitants of the Chagos Archipelago are referred to as Chagossians and, sometimes, as the “Ilois” or “islanders”. In this Opinion these terms are used interchangeably.

  1. On 7 August 1967, general elections were held in Mauritius and the political parties in favour of independence prevailed.

  1. Between 1967 and 1973, the entire population of the Chagos Archipelago was either prevented from returning or forcibly removed and prevented from returning by the United Kingdom. The main forcible removal of Diego Garcia’s population took place in July and September 1971.

And, according to Wikipedia:

Diego Garcia is an island of the British Indian Ocean Territory, an overseas territory of the United Kingdom. It is a militarised atoll just south of the equator in the central Indian Ocean, and the largest of 60 small islands comprising the Chagos Archipelago.


In March 1971, United States Naval construction battalions, (Seabees), arrived on Diego Garcia to begin the construction of the communications station and an airfield.

What are the consequences of ignoring a UN resolution?

That depends. As noted in Sjoerd's answer, the UN General Assembly cannot enforce it resolutions and the UK has a veto in the Security Council which can enforce its resolutions.

That said, the reason it comes up now, according to Southern Africa correspondent Andrew Harding for the BBC:

Over the decades Mauritius has staked its claim, and finally - particularly after the Brexit vote - Britain's traditional allies in the international community have started to desert Britain, to abstain or to vote against it at the UN.

And the UN is now taking pretty significant steps to say: "Britain you are behaving appallingly, this is still colonialism - give it back."

Britain has ignored those calls - so what might any repercussions look like?

Sanctions would be slow, incremental and largely institutional - in the sense that Britain is going to find itself squeezed at institutions that it has traditionally seen as very important.

Britain no longer has a judge on 14-seat International Court of Justice in The Hague, and it's going to start to see UN maps reflecting the legal fact that the UN sees this islands as belonging to Mauritius.

The deadline is not binding, so no sanctions or immediate punishment will follow - but that could change.

So while it's not directly enforceable, it may be seen as part of a geopolitical shift. Some countries that have historically sided with the United Kingdom may look for other alliances in which there is more to gain for them.

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    A disputed claim doesn't mean that the claim is invalid. Disputed just means that there is a second claim. As a result, UK's claim can both be valid and disputed.
    – Sjoerd
    Commented Nov 22, 2019 at 22:22
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    -1 for "it's disputed". Because when international bodies rule that China has no right to sovereignty in the South China sea it's not. Commented Nov 22, 2019 at 22:24
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    @dan-klasson the situation in the South Chin Sea you refer to is also rather famously referred to as a dispute. See for example this Wikipedia page: Territorial disputes in the South China Sea. That the situation is unenforceable is a different thing, but it's still a dispute.
    – JJJ
    Commented Nov 23, 2019 at 0:07
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    @JJforTransparencyandMonica But disputed or not wasn't the question - in fact, the question itself already proves it is contested by naming the opposing claim. The question is whether the claim was valid.
    – Sjoerd
    Commented Nov 23, 2019 at 1:32
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    @dan-klasson - Singing the same old tune? China's disputed claim to one territory has almost nothing to do with Britain's disputed claim to another. You seem to be dragging a totally different topic into this answer. The term used in this answer is correct. Britain's government (and, presumably, some allies) claim that it deserves control of the islands. Mauritius (and many other countries) do not. By contrast, Britain's control of Cork, for instance, is significantly less disputed, and probably not by any foreign country.
    – Obie 2.0
    Commented Nov 24, 2019 at 19:17

Is the UK’s claim over the Chagos Islands valid?


In international politics, the only thing that matters is the ability to enforce a claim.

Resolutions by the UN general assembly are usually ignored by the major powers because the UN general assembly cannot enforce its resolutions. The UN Security Council can enforce its resolutions, but the UK has a veto there.

The UK has ruled that island for two centuries, and nobody has been able to remove them from the island in that period - Mauritius certainly cannot.

Therefore, the UK's claim is valid.

The last country to challenge a UK claim, was Argentina during the Falkland War in 1982. Argentina's military at that time was much stronger than Mauritius'. Still, the UK won that war in about 10 weeks, while the contested islands are 500 km from Argentina and 12,000 km from Great Britain. The UK proved that they were able to enforce their claim across half the globe.

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    I bet you don't say that when it comes to the South China sea Commented Nov 22, 2019 at 22:25
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    @dan-klasson You lost. I even say that about the Golan Heights and Crimea.
    – Sjoerd
    Commented Nov 22, 2019 at 22:27
  • Ok then I'll undo my downvote then. Commented Nov 22, 2019 at 22:28
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    @dan-klasson as long as the US is willing to send aircraft carriers to the South China Sea to maintain the status quo, it will remain neutral. As soon as it stops, it will become a property of China. Commented Nov 22, 2019 at 23:41
  • @JonathanReezSupportsMonica Yeah I get that. But it's the hypocrisy I have a problem with. I'm not in the business of supporting communism. Commented Nov 22, 2019 at 23:51

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