1965 – Britain separates the Chagos Archipelago from Mauritius, creating the British Indian Ocean Territory and clearing the area for a future U.S. base [5].

1966 – The United Kingdom and United States sign a defense treaty governing the British Indian Ocean Territory, establishing the legal framework for the joint Diego Garcia installation [2][3].

2008 – Diego Garcia is used for clandestine rendition flights, later acknowledged as part of the island’s controversial security history [5].

2024 – A political shift in Mauritius revives negotiations on Chagos sovereignty, setting the stage for a formal treaty the following year [4].

May 2025 – The United Kingdom and Mauritius sign a treaty transferring sovereignty of the Chagos Islands to Mauritius while retaining a 99‑year lease of Diego Garcia for the U.K. and U.S., with an average annual payment of £101 million and a net cost of £3.4 billion to Britain [4][8][9][10].

May 2025 – The United States publicly welcomes the UK‑Mauritius agreement, with Secretary of State Marco Rubio noting that President Trump had expressed support for the deal during a White House meeting with Prime Minister Keir Starmer [4].

May 2025 – The United Nations General Assembly and the International Court of Justice call on Britain to end its colonial administration of the Chagos Archipelago and recognize Mauritian sovereignty [10].

Jan 20, 2026 – President Donald Trump posts on Truth Social that the Chagos handover is “great stupidity,” arguing it weakens U.S. security, while the U.K. government asserts the deal “does not compromise national security” and the parliamentary bill moves toward final passage [3][8][9][10].

Jan 20, 2026 – A Whitestone Insight poll of more than 3,600 Chagossians shows overwhelming support for remaining British and opposition to the transfer, highlighting community resistance [4].

Jan 21, 2026 – Prime Minister Keir Starmer accuses Trump of shifting his stance to pressure Britain over Greenland, noting that Trump’s earlier comments had welcomed the Chagos deal [7].

Jan 21, 2026 – The European Union discusses possible retaliatory tariffs on U.S. goods if Trump proceeds with his Greenland tariff plan, linking the Chagos dispute to broader trans‑Atlantic tensions [7].

Jan 26, 2026 – The U.K. Foreign Office reaffirms that the Chagos handover remains “the best path forward,” despite Trump’s criticism, while Minister Stephen Doughty calls a Conservative amendment in the Lords a “wrecking amendment” that threatens national security [2].

Jan 26, 2026 – Opposition parties demand clarification of the 1966 U.K.–U.S. treaty before ratifying the agreement, fearing the new arrangement could breach existing obligations [2].

Feb 1, 2026 – Maldives President Mohamed Muizzu announces a proposal to assume Chagos sovereignty while preserving the U.S. base, pledging to seek parliamentary approval and citing historic Maldivian ties to the archipelago [6].

Feb 1, 2026 – Trump again denounces the U.K.–Mauritius handover on Truth Social, calling it “an act of GREAT STUPIDITY” and insisting the U.S. should instead acquire Greenland for security [6].

Feb 5, 2026 – Trump warns that the United States will “militarily secure Diego Garcia” if the lease is ever threatened, referencing recent B‑2 Spirit bomber deployments from the island and his “very productive discussions” with Starmer [5].

Feb 18, 2026 – Trump urges the United Kingdom “Do not give away Diego Garcia,” labeling any transfer a “blight on our Great Ally,” while the U.S. State Department officially backs the UK‑Mauritius agreement and the U.K. Foreign Office says the 99‑year lease‑back guarantees the base’s future [1].

Feb 18, 2026 – Four Chagossians land on the atoll to protest the handover, refusing eviction despite a British maritime patrol’s warning, underscoring ongoing local opposition [1].

2026 (future) – The U.K. parliamentary bill to embed the UK‑Mauritius treaty is expected to complete the “ping‑pong” process between the Commons and Lords and receive Royal Assent later in 2026, finalizing the sovereignty transfer and lease arrangement [2][3].

2026 (future) – Maldives lawmakers are slated to vote on the proposed sovereignty transfer, which would keep the Diego Garcia base operational under a new Maldivian‑British lease framework [6].

2026 (future) – Discussions on a Chagossian resettlement fund continue in the U.K. Parliament, aiming to provide compensation for displaced islanders as the handover proceeds [9].