Silence Is Not a Deed of Surrender: Why Estoppel and Acquiescence Do Not Foreclose the Folhlhavai (Chagos) Claim

Status note: This article reflects legal and diplomatic developments as of 1 September 2026. The status of the UK-Mauritius arrangements concerning Folhlhavai remains subject to ongoing political, legislative and diplomatic developments.

The Sixty-Year Objection

The most convenient objection to an antecedent Maldivian claim over Folhlhavai is also the most seductive. If these islands were Maldivian territory, why did Maldives remain silent for sixty years? Add the language of acquiescence and estoppel, and political silence begins to sound almost like a deed of surrender. International law is not quite so accommodating. Before silence can extinguish an earlier title, one must establish what that title was, whose sovereignty Maldives supposedly accepted, and when circumstances actually arose that required Maldives to protest.

Those questions have become more urgent because the future sovereignty of Folhlhavai is unsettled. Britain has sought to transfer sovereignty to Mauritius while retaining the UK-US military facility on Foalhavahi. Maldives has formally objected. Mauritius has responded by suspending diplomatic relations with Maldives. The question is therefore no longer merely why previous Maldivian governments failed to formulate an antecedent claim. The immediate question is whether Maldives should remain silent while other States determine the future of territory for which historical evidence indicates an antecedent Maldivian title.

Maldives Was Left Out in 1946

The institutional imbalance began before Maldivian independence. In 1946, Mauritius entered the United Nations framework for Non-Self-Governing Territories. Maldives did not. This omission did not deprive independent Maldives of international personality or the capacity to advance territorial claims. It did, however, produce very different institutional histories. Mauritius acquired a recognised decolonisation file through which the 1965 separation of Folhlhavai could eventually be challenged before the United Nations and, through the General Assembly, the International Court of Justice (UNGA Res 66(I), 14 December 1946).

Maldives possessed no comparable decolonisation pathway. That difference matters when later silence is assessed. The two States did not emerge into the post-colonial international order carrying equivalent institutional tools with which to contest colonial territorial arrangements.

Britain Made Folhlhavai a British Colony

Four months after Maldivian independence, Britain made the British Indian Ocean Territory Order 1965. Folhlhavai and several islands detached from Seychelles were constituted as a “separate colony” called the British Indian Ocean Territory (BIOT Order 1965, ss 3–4). Mauritius was not yet independent.

A Maldivian territorial challenge in 1965 would therefore not have been directed against Mauritius. It would have challenged Britain itself. For decades afterwards Britain administered BIOT and defended its sovereignty internationally. That elementary fact tends to disappear when six decades of very different political circumstances are compressed retrospectively into “Maldivian acquiescence”.

A Claim Against Britain Was No Small Matter

Nor would such a challenge have been a contest between equals. Maldives had only just emerged from British protection. Britain had controlled Maldivian external relations and remained one of the world’s principal diplomatic and military powers. At precisely this time, Foalhavahi was acquiring exceptional importance to Anglo-American strategy in the Indian Ocean.

Maldives lacked Britain’s diplomatic, financial and legal resources. It also lacked the UN decolonisation machinery through which Mauritius would later pursue its case. None of this makes silence legally meaningless. It makes context legally indispensable. Sixty years of silence may demand an explanation. It does not write the explanation for us.

Mauritius Did Not Constitutionally Include Folhlhavai at Independence

There is another problem with automatically starting an acquiescence clock in 1965. Following the British detachment, Folhlhavai was not included within the territorial definition of independent Mauritius under section 111 of its 1968 Constitution. Mauritius subsequently made its territorial position increasingly explicit. Statutory inclusion came in 1982, followed by express constitutional inclusion in 1992.

This does not defeat Mauritius’s decolonisation case. The ICJ concluded in 2019 that the detachment was unlawful and that Mauritian decolonisation had not been lawfully completed (Chagos Advisory Opinion, ICJ Reports 2019). But it does mean that the stronger acquiescence argument begins later, when Mauritius’s claim became sufficiently explicit and internationally visible to raise the question whether a contrary claimant should have responded. That is a more serious argument than simply counting from 1965. It is also more revealing, because Maldives eventually did respond.

So Whose Sovereignty Did Maldives Acquiesce In?

For decades Britain said Folhlhavai was British. Mauritius said it was Mauritian. Maldives did not formulate an affirmative antecedent claim. If Maldivian silence is now to be transformed into consent, the obvious question remains as consent to whose sovereignty?

In Pedra Branca, the ICJ recognised that silence may speak when another State’s conduct calls for a response. But the Court also required clarity where sovereignty is said to have passed through conduct (Malaysia/Singapore, Judgment, ICJ Reports 2008, paras 121–122). Silence towards British administration cannot simply be carried across history and deposited into Mauritius’s legal account. The claimant, the conduct requiring protest and the legal significance of the failure to protest must first be established. Otherwise “acquiescence” becomes a label for the question rather than an answer to it.

When Mauritius Asserted Its Claim, Maldives Did Not Simply Acquiesce

The post-1980 record therefore deserves particular attention. When the General Assembly voted in 2017 on Resolution 71/292 requesting the ICJ Advisory Opinion, Maldives voted against it. After the Court delivered its opinion, Maldives again voted against Resolution 73/295 in 2019. Neither vote asserted Maldivian sovereignty. But neither resembles recognition of Mauritian sovereignty.

The ITLOS proceedings provide even stronger evidence. In its preliminary objections in the Mauritius/Maldives maritime delimitation case, Maldives formally maintained that sovereignty over Folhlhavai remained disputed between Britain and Mauritius. It argued that the Special Chamber could not simply proceed upon the assumption of Mauritian sovereignty. The Chamber rejected those objections in January 2021, but that does not erase the position Maldives actually took before an international tribunal (Mauritius/Maldives, Preliminary Objections, Judgment of 28 January 2021).

The distinction is crucial. Non-assertion of Maldivian title is not synonymous with acquiescence in Mauritian title. The former describes what Maldives failed to claim. The latter requires evidence of what Maldives accepted.

The Solih Letter Was a Reversal, Not Sixty Years of Acquiescence

President Ibrahim Mohamed Solih’s 2022 letter must nevertheless be confronted. His administration shifted Maldivian policy towards supporting Mauritius on the decolonisation question. In 2023, the President’s Office also stated that Maldives had never claimed sovereignty over the Chagos Archipelago. This is adverse State conduct. Any serious Maldivian case must address its language, intention and possible legal consequences.

But the Solih position did not become settled Maldivian policy. The succeeding government formally objected to Britain over the proposed transfer on 8 November 2024. A further written objection followed on 18 January 2026. President Mohamed Muizzu also raised the issue directly with British Deputy Prime Minister David Lammy on 15 December 2025. These were not merely speeches intended for a domestic audience. They were communications addressed to the State administering the territory and proposing to alter its sovereign disposition.

On 5 February 2026, Muizzu formally withdrew Solih’s letter of 22 August 2022 and communicated that decision to the Prime Minister of Mauritius. The significance goes beyond a change of government. Following a review of the previous administration’s conduct in the ITLOS proceedings, the President invoked Article 115(o) of the Constitution to establish a national inquiry into the matter. The President’s Office described Solih’s earlier action as a “shift” in the Maldivian position and recorded the Government’s view that it had adversely affected Maldivian interests.

Withdrawal cannot automatically erase whatever legal consequences the earlier letter may have produced. But neither can a policy adopted in 2022 manufacture continuous acquiescence retrospectively back to 1965. The record instead shows opposition at the UN, formal resistance before ITLOS, a reversal under Solih, subsequent objections directly to Britain, and finally the formal withdrawal of the Solih position. That is contested and sometimes inconsistent State practice. It is not serene acquiescence.

Estoppel Requires More Than the Passage of Time

Estoppel provides no easier shortcut. In Bolivia v Chile, the ICJ identified the relevant elements as a representation or statement, reliance by another State, and resulting detriment or advantage (Bolivia v Chile, Judgment, ICJ Reports 2018, para 158).

What Maldivian representation renounced antecedent title? Who relied upon it? What position did Britain or Mauritius adopt because of that representation? What detriment resulted? The passage of sixty years answers none of those questions. Failure by successive governments to discover or formulate an older claim may be politically inconvenient, but it is not necessarily juridical abandonment. A forgotten claim and an abandoned claim are not the same thing. Estoppel cannot be manufactured from a calendar.

Lancaster House itself demonstrates what an established estoppel looks like in the legal history of Folhlhavai. The 2015 Tribunal identified specific British undertakings to Mauritius, examined their subsequent reaffirmation and legal effect, and held that the United Kingdom was estopped from denying their binding character. No comparable course of Maldivian representation has yet been identified by which Maldives renounced an antecedent title and Britain or Mauritius relied upon that representation in circumstances capable of generating an estoppel. Elapsed time cannot supply the missing representation (Chagos Marine Protected Area Arbitration, Award, 18 March 2015, para 448).

Why Now? The Future Sovereignty of Folhlhavai Is Unsettled

The present moment is different because the sovereign disposition itself is now contested. Britain signed an agreement in May 2025 intended to recognise Mauritius as sovereign while preserving the UK-US facility on Foalhavahi. The process subsequently encountered political and legislative difficulties. Meanwhile Maldives formally opposed the transfer. On 27 February 2026, Mauritius responded by suspending diplomatic relations with Maldives, expressly citing the Maldivian Government’s non-recognition of Mauritian sovereignty and its objection to the UK-Mauritius agreement.

That diplomatic rupture matters. This is no longer an argument confined to archives, old maps or academic seminars. The Maldivian position has entered interstate relations. Mauritius itself has treated it as sufficiently consequential to suspend diplomatic ties. The question is therefore not why Maldives has suddenly become interested in old history. The question is why Maldives should remain silent precisely when the future sovereign status of Folhlhavai is being determined.

There are contemporary interests as well. The UK-US facility contributes to the wider security architecture of the Indian Ocean. Maldives can recognise that strategic value without conceding the underlying territorial title. The maritime space surrounding Folhlhavai also matters to Maldivian fisheries and environmental security. The question is not whether a change of sovereignty automatically produces industrial fishing. It is who will exercise long-term authority over conservation, fisheries policy and maritime enforcement immediately south of Maldives.

Lancaster House Does Not Begin the Chain of Title

The Lancaster House arrangements of September 1965 present a more serious question for any antecedent Maldivian claim. Among the undertakings given by Britain was that Folhlhavai would be returned to Mauritius when the islands were no longer required for defence purposes. The arrangements also concerned compensation, fishing rights, mineral and oil benefits and other facilities. The 2015 arbitral tribunal subsequently held that the relevant British undertakings had become binding upon the United Kingdom after Mauritian independence and found Britain estopped from denying their binding effect. The ICJ, for its part, recorded that Mauritian representatives agreed in principle to detachment on condition that the archipelago could not be ceded to a third party and would later be returned to Mauritius (Chagos Advisory Opinion, ICJ Reports 2019, paras 108–112, 171).

That evidence should not be minimized. Lancaster House establishes a substantial legal relationship between Britain and Mauritius concerning Folhlhavai at the moment of Mauritian decolonisation. The ICJ went further. It held that, at the time of detachment in 1965, Folhlhavai was “clearly an integral part” of the Non-Self-Governing Territory of Mauritius. It concluded that the detachment was not based upon the free and genuine expression of the will of the people concerned, that Britain was required to respect the territorial integrity of colonial Mauritius including the archipelago, and that Mauritius’s decolonisation was consequently not lawfully completed in 1968 (Chagos Advisory Opinion, paras 170–174).

A Maldivian antecedent-title argument need not contest any of those findings. The question is not whether Folhlhavai formed part of the colonial territory of Mauritius in 1965. The ICJ has answered that question. The anterior question is how sovereignty over Folhlhavai originated before it became incorporated into that colonial territorial structure, and whether any antecedent Maldivian title had already been lawfully extinguished.

That distinction is fundamental. Lancaster House regulated what Britain undertook to do with territory over which Britain claimed sovereignty in 1965. It did not investigate the juridical origin of that sovereignty. It did not determine whether an earlier Maldivian title existed, how France acquired sovereignty against Maldives, or whether such a title had been extinguished before Britain acquired the islands from France. The 2015 Tribunal’s finding of estoppel similarly concerned Britain’s undertakings to Mauritius. It did not adjudicate an antecedent Maldivian title.

Lancaster House therefore strengthens Mauritius’s position concerning the legal relationship between Britain and Mauritius at decolonisation. It does not eliminate the anterior inquiry. If historical evidence establishes that Folhlhavai was previously subject to Maldivian sovereignty, the question remains: by what juridical process did that title disappear before France, Britain and eventually colonial Mauritius came to deal with the territory as they did? Lancaster House belongs within that chain of title. It cannot substitute for the beginning of it.

First Determine the Antecedent Title

Lancaster House therefore makes the sequencing question more important, not less. None of the foregoing proves Maldivian sovereignty. That case must stand or fall on historical and legal evidence. But neither the Lancaster House undertakings, the 2015 arbitral award nor the 2019 Advisory Opinion adjudicated whether an antecedent Maldivian title existed before European acquisition. Their relevant inquiries begin centuries later.

Significantly, antecedent title is no longer merely an argument being advanced outside government. In its 5 February 2026 statement, the President’s Office referred expressly to historical evidence of Maldivian connections with Foalhavahi. It singled out a sixteenth-century royal instrument by a Maldivian Sultan asserting sovereignty over the archipelago as part of the historical basis for the present Government’s position. The official release itself describes the evidence as including a sixteenth-century “royal decree”.

That official statement is important as evidence of present Maldivian State practice. It should not, however, be mistaken for proof of the historical proposition itself. The sixteenth-century instrument must be identified, authenticated and interpreted on its own terms. Its geographical language must be tested against contemporary records and cartography. The legal significance of the Sultan’s titulature or declaration must likewise be assessed in its historical context. A modern presidential statement cannot perform that evidentiary work for it.

The legal investigation must therefore travel further back. If the historical record establishes an antecedent Maldivian title, how did France acquire Folhlhavai against that title? What acts constituted the purported acquisition? Was there conquest, cession, occupation of territory regarded as terra nullius, prescription, recognition or some other juridical basis available under the law applicable at the time? What precisely did Britain then acquire from France in 1814? Only after those questions have been answered can the later administrative relationship with Mauritius and the Lancaster House arrangements be placed correctly within the chain of title.

The ICJ’s 2019 Advisory Opinion conclusively answered the decolonisation question placed before it. It held that the separation of the archipelago from Mauritius was unlawful and that the decolonisation of Mauritius had not been lawfully completed. It did not adjudicate an affirmative Maldivian sovereignty claim predating European acquisition. Respect for the Court requires respecting both propositions.

The sixty-year objection therefore begins the inquiry at the wrong end. First establish the title. Then trace what happened to it. Only afterwards can silence, acquiescence, abandonment and estoppel be properly weighed. Silence may become evidence and, in appropriate circumstances, consent. But it cannot relieve international law of the anterior question. What title existed, and how was it supposedly lost? Sixty years of silence may be evidence. It is not a deed of surrender.

References

British Indian Ocean Territory Order 1965, SI 1965/1920, ss 3–4.

Constitution of Mauritius 1968, s 111; Interpretation and General Clauses legislation, as amended in 1982.

United Nations General Assembly, Resolution 66(I), Transmission of Information under Article 73(e) of the Charter, 14 December 1946.

United Nations General Assembly, Resolution 71/292, Request for an Advisory Opinion of the International Court of Justice on the Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, 22 June 2017.

United Nations General Assembly, Resolution 73/295, Advisory Opinion of the International Court of Justice on the Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, 22 May 2019.

Sovereignty over Pedra Branca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia/Singapore), Judgment, ICJ Reports 2008, paras 121–122.

Obligation to Negotiate Access to the Pacific Ocean (Bolivia v Chile), Judgment, ICJ Reports 2018, para 158.

Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion, ICJ Reports 2019, particularly paras 108–112, 170–174.

Chagos Marine Protected Area Arbitration (Mauritius v United Kingdom), Award, 18 March 2015, Reports of International Arbitral Awards, vol XXXI, particularly para 448.

Dispute concerning Delimitation of the Maritime Boundary between Mauritius and Maldives in the Indian Ocean (Mauritius/Maldives), Preliminary Objections, Judgment of 28 January 2021.

Agreement between the Government of the United Kingdom and the Government of the Republic of Mauritius concerning the Chagos Archipelago including Diego Garcia, signed 22 May 2025.

President’s Office, Republic of Maldives, ‘President withdraws 2022 letter issued by former administration on the Government’s Position on Chagos Archipelago Advisory Opinion of ICJ’, Ref 2026-065, 5 February 2026.

President’s Office, Republic of Maldives, Presidential Address 2026, 5 February 2026.

Ministry of Foreign Affairs, Regional Integration and International Trade, Republic of Mauritius, Statement on the Suspension of Diplomatic Relations with the Republic of Maldives, 27 February 2026.