Relationship dossier
Mauritius
United Kingdom
Relationship assessment
Bilateral engagement is shaped by cooperation and the long-running Chagos sovereignty dispute.
Mauritius toward United Kingdom
-15Mauritius has consistently challenged the United Kingdom's control of the Chagos Archipelago, including through international legal and diplomatic action. The 2025 treaty provides for Mauritius to exercise sovereignty while permitting continued British use of Diego Garcia under a long-term arrangement.
United Kingdom toward Mauritius
-15The United Kingdom retained control of the Chagos Archipelago despite Mauritius's sovereignty claim and international calls for decolonization. In 2025, it signed a treaty providing for Mauritian sovereignty alongside continued British use of Diego Garcia under a long-term arrangement.
Overall relationship
-10The relationship combines established bilateral engagement with a major, enduring sovereignty dispute. The 2025 treaty represents a significant negotiated framework for resolving the Chagos issue, while its implementation and the future arrangements for Diego Garcia remain central to the relationship.
How to read these scores
Scores are rough judgments, not objective measurements or current verification. Directional scores describe government policy and conduct, not public opinion. The overall score is an independent estimate, never an average.
- −100
- Extreme sustained hostility
- −50
- Substantially adversarial
- 0
- Mixed or neutral, supported by knowledge
- +50
- Substantially cooperative
- +100
- Exceptionally close sustained partnership
“Not assessed” means there is no recorded score. Pair existence makes no claim about diplomatic recognition or established relations.
Relationship context
Overview
Mauritius and the United Kingdom maintain broad bilateral engagement, but the Chagos Archipelago sovereignty dispute has been a sustained source of friction. Mauritius has pursued its claim through diplomatic and international legal channels, while the United Kingdom long retained control of the islands. A 2025 treaty provides for Mauritius to exercise sovereignty while the United Kingdom retains rights to operate the Diego Garcia base under a long-term arrangement.
Areas of tension
- Sovereignty over the Chagos Archipelago and the consequences of its separation from Mauritius before independence.
- The future governance and resettlement arrangements concerning the Chagos Archipelago.
- The terms and implementation of continued United Kingdom use of the Diego Garcia military base.
Key developments
The International Court of Justice issued an advisory opinion concluding that the United Kingdom's administration of the Chagos Archipelago should end and that the decolonization of Mauritius had not been lawfully completed.
The United Nations General Assembly adopted a resolution calling on the United Kingdom to end its administration of the Chagos Archipelago.
Mauritius and the United Kingdom signed a treaty providing for Mauritian sovereignty over the Chagos Archipelago and continued British use of Diego Garcia under a long-term arrangement.
Major uncertainties
- The treaty's implementation and the practical arrangements for Diego Garcia remain important elements of the relationship.
- The scope and implementation of other bilateral cooperation are unclear.