The PCA’s award in Rwanda v. United Kingdom turns a politically charged migration dispute into a careful lesson in treaty interpretation, diplomatic correspondence and the legal consequences of saying “acceptable” in a note verbale. Although the case arose from the Rwanda-UK Asylum Partnership Agreement (the “Asylum Partnership Agreement”), its importance extends beyond asylum policy. The Tribunal’s reasoning is relevant for States, counsel and international arbitration practitioners because it addresses when diplomatic exchanges can amend binding obligations, how tribunals assess consent, and what evidence is needed to prove breach of an obligation to negotiate.
Case at a Glance
Republic of Rwanda v. United Kingdom of Great Britain and Northern Ireland, PCA Case No. 2025-45, 2026.[1]
Facts
The dispute arose from the Rwanda-UK Migration and Economic Development Partnership. The Parties first recorded their cooperation in a 2022 Memorandum of Understanding, which was not binding in international law and was intended to create a mechanism for relocating certain asylum seekers from the UK to Rwanda for processing and settlement or removal.[2]
After the UK Supreme Court held in AAA v Secretary of State for the Home Department that the removal policy was unlawful, Rwanda and the UK formalised the partnership by signing the binding Asylum Partnership Agreement on 5 December 2023. The legally decisive provisions were Article 18, which required the Parties to make financial arrangements in support of relocation, and Article 19, which required arrangements for the UK to resettle a portion of Rwanda’s most vulnerable refugees.[3]
In June 2024, the Parties concluded a finance agreement (the “2024 Finance Agreement”) by exchange of notes. The UK’s initiating note verbale in that exchange was referred to as the “2024 Finance Note” or “Finance Note”, and set out the financial arrangements under Article 18, including the ETIF payment schedule. The Tribunal recorded that the Parties agreed this was binding under international law. The 2024 Finance Agreement preserved the Economic Transformation and Integration Fund, a funding stream intended to support Rwanda’s broader economic-development and integration objectives, under which Year 2 and Year 3 payments of GBP 50 million each were due annually within 10 days of 13 April in each year.[4]
After a change of UK government, the UK notified Rwanda on 8 July 2024 that no future removals to Rwanda were scheduled or intended. In November 2024, the Parties exchanged notes verbales dated 13 and 14 November 2024, which the Tribunal referred to together as the “November 2024 Notes Verbales”. In those notes, the UK asked Rwanda to forgo additional payments under the Economic Transformation and Integration Fund. The UK’s Technical Annex stated that the GBP 50 million payments due in April 2025 and April 2026 would not be paid and that the Finance Note was amended accordingly. Rwanda replied that the proposed arrangements were acceptable. Rwanda later sought to rescind the November 2024 arrangements, but the Tribunal held that Rwanda could not unilaterally undo a bilateral amendment.[5]
Procedural History
The case reached the PCA-administered Tribunal through the dispute settlement mechanism in Article 22 of the Asylum Partnership Agreement.
Rwanda first referred the dispute to the Joint Committee on 24 March 2025. The Joint Committee met on 16 April 2025, but the dispute was not resolved. Political consultations then took place on 4 June 2025, again without resolution. Rwanda commenced arbitration on 24 November 2025. The Tribunal was composed of Judge Peter Tomka as Chairperson, Professor Dr Mohamed Abdel Wahab, and Judge Joan Donoghue. The hearing took place at the Peace Palace in The Hague from 18 to 20 March 2026. The Tribunal issued its Award on 15 May 2026.[6]
In parallel, the UK repealed the Safety of Rwanda Act, the domestic legislation enacted to support implementation of the Rwanda removal policy under the Asylum Partnership Agreement, through the Border Security, Asylum and Immigration Act 2025, formally notified Rwanda of termination of the Asylum Partnership Agreement on 16 December 2025, and termination became effective on 16 March 2026.[7]
Issues
The Tribunal had to decide two central questions.
First, did the November 2024 Notes Verbales amend the 2024 Finance Agreement so that the UK no longer owed Rwanda the Year 2 and Year 3 Economic Transformation and Integration Fund payments? If not, did the UK breach Article 18 of the Asylum Partnership Agreement by failing to maintain or make further financial arrangements?
Second, did the UK breach Article 19 of the Asylum Partnership Agreement by failing to make arrangements to resettle a portion of Rwanda’s most vulnerable refugees in the UK?
Rule and Holding
The Tribunal applied the Vienna Convention on the Law of Treaties (the “VCLT”), to which both the UK and Rwanda are parties, to both the Asylum Partnership Agreement and the 2024 Finance Agreement. It held that States may conclude or amend agreements through exchanges of diplomatic notes. No special form is required. The decisive question is whether the Parties intended to be bound. Even where the exchanged texts do not, by themselves, prove consent under Article 13(1)(a) of the VCLT, intent may be established under Article 13(1)(b) by the circumstances of the exchange, prior negotiations, draft history, and subsequent conduct.[8]
On the financial arrangements claim, the Tribunal held by majority that Rwanda accepted the November 2024 proposal and thereby amended paragraphs 2.3.1 and 2.3.2 of the 2024 Finance Agreement. The Tribunal rejected Rwanda’s Year 2 claim for GBP 50 million by majority. It rejected Rwanda’s Year 3 claim for GBP 50 million, or alternatively GBP 10.4 million pro rata, unanimously. It also unanimously rejected Rwanda’s claim that the UK breached Article 18 of the Asylum Partnership Agreement.[9]
On the resettlement claim, the Tribunal held that Article 19 created a joint obligation to make arrangements through good-faith negotiations, but the record did not show that Rwanda had submitted a concrete proposal for resettlement arrangements or that the UK had failed to meet the obligation. The Tribunal unanimously rejected Rwanda’s Article 19 claim.[10]
Reasoning and Disposition
The Tribunal’s reasoning turned on consent, documentary record, and the difference between a duty to make arrangements and an obligation to achieve a specific financial or resettlement outcome.
On the financial arrangements claim, the Tribunal accepted that the text of the November 2024 exchange did not, taken alone, unambiguously satisfy Article 13(1)(a) of the VCLT. Rwanda’s reply did not expressly state that the exchange would place on record a binding understanding between the two Governments, nor did it specify a date of entry into force. But the Tribunal held that this was not the end of the inquiry. Under Article 13(1)(b), the Parties’ intention could be established otherwise.[11]
The majority then looked at the surrounding circumstances. The Parties had exchanged successive drafts. Rwanda had proposed the language asking Rwanda to forgo additional Economic Transformation and Integration Fund payments “in anticipation of the formal termination” of the Agreement. The UK then issued a Note Verbale and Technical Annex stating that the April 2025 and April 2026 payments would not be paid and that the Finance Note was amended. Rwanda replied that the proposed arrangements were acceptable, without reservations or limitations. The majority treated that reply as consent to amend the 2024 Finance Agreement and to forgo additional Economic Transformation and Integration Fund payments.[12]
The Tribunal also rejected Rwanda’s later attempt to rescind the November 2024 arrangements. Once the Parties had agreed on the amendment, Rwanda could not withdraw its consent unilaterally months later. Any further amendment required mutual consent.[13]
Article 18 did not revive Rwanda’s financial claim. The Tribunal reasoned that Article 18 required the Parties to make financial arrangements in support of relocation. The Parties had done so through the June 2024 Finance Agreement, and those arrangements were later modified in November 2024. The Tribunal also noted that the UK had notified Rwanda that no further removals were scheduled or intended, and that the Agreement did not oblige the UK to request relocations. It found it unrealistic to conclude that the UK remained under a continuing duty to negotiate further financial arrangements until termination of the Agreement.[14]
On Article 19, the Tribunal treated the resettlement obligation as a joint obligation. Arrangements for resettling a portion of Rwanda’s most vulnerable refugees could only result from an agreement between the Parties. That required good-faith negotiation. But the Tribunal found no evidence that either Party pursued Article 19 negotiations between December 2023 and March 2025. When Rwanda raised the issue on 24 March 2025, it did so in a dispute letter and did not attach a concrete proposal. The Joint Committee meeting and political consultations did not produce a record showing any specific proposal. The Tribunal also refused to accept counsel’s statement, made on instructions, as evidence that Rwanda had submitted one.[15]
The disposition was dismissal of all claims. The Tribunal rejected the Year 2 financial claim by majority; rejected the Year 3 financial claim unanimously; rejected the Article 18 claim unanimously; and rejected the Article 19 claim unanimously. It ordered each Party to bear its own legal costs and split the arbitration costs equally. Professor Dr Mohamed Abdel Wahab signed subject to a dissenting and separate opinion.[16]
Conclusion
This decision is relevant beyond the Rwanda-UK migration context. It shows that diplomatic notes can have binding legal consequences, including amendments to treaty-linked financial obligations, where the surrounding record shows consent. It also shows the importance of precision in treaty-linked financial drafting. Words such as “acceptable”, “forgo”, “amended”, and “arrangements” may become decisive when a tribunal reconstructs the Parties’ intent.
The award is also a practical reminder about obligations to negotiate. A party alleging breach of such an obligation should be able to point to concrete proposals, meeting records, correspondence, or other evidence showing that negotiations were requested and obstructed. Political dissatisfaction is not enough. In inter-State disputes, the paper trail may determine whether a diplomatic exchange is merely political or legally binding.
[1] Republic of Rwanda v. United Kingdom of Great Britain and Northern Ireland, PCA Case No. 2025-45, Award, 15 May 2026, ¶¶ 1-5; Permanent Court of Arbitration, Arbitration pursuant to the Asylum Partnership Agreement (The Republic of Rwanda v. The United Kingdom of Great Britain and Northern Ireland), PCA Case Repository (last accessed 1 June 2026).
[2] Rwanda v. UK, Award, ¶¶ 28-31.
[3] AAA v Secretary of State for the Home Department [2023] UKSC 42; [2023] 1 WLR 4433, ¶¶ 1, 149; Rwanda v. UK, Award, ¶¶ 41-46.
[4] Rwanda v. UK, Award, ¶¶ 53-58.
[5] Rwanda v. UK, Award, ¶¶ 63-65, 88-96, 100-101, 195-201.
[6] Rwanda v. UK, Award, ¶¶ 4-26, 101-103.
[7] Rwanda v. UK, Award, ¶¶ 104-106.
[8] Vienna Convention on the Law of Treaties, opened for signature 23 May 1969, entered into force 27 January 1980, Art. 13; Rwanda v. UK, Award, ¶¶ 109-111, 173-176.
[9] Rwanda v. UK, Award, ¶¶ 195-197, 202-204, 251.
[10] Rwanda v. UK, Award, ¶¶ 238-249, 251.
[11] Rwanda v. UK, Award, ¶¶ 173-176.
[12] Rwanda v. UK, Award, ¶¶ 188-197.
[13] Rwanda v. UK, Award, ¶¶ 198-202.
[14] Rwanda v. UK, Award, ¶¶ 203-204.
[15] Rwanda v. UK, Award, ¶¶ 238-249.
[16] Rwanda v. UK, Award, ¶¶ 250-251; Permanent Court of Arbitration, Arbitration pursuant to the Asylum Partnership Agreement (The Republic of Rwanda v. The United Kingdom of Great Britain and Northern Ireland), PCA Case Repository (last accessed 1 June 2026) (listing the Dissenting and Separate Opinion of Prof. Dr Mohamed Abdel Wahab).
