If distance is anything to go by then the Chagos Islands should be a part of the Maldives which the islands are 600 miles closer to than they are to Mauritius. [1] Moreover the Maldives are on the same geographical feature as the Chagos islands; the Chagos-Maldives-Laccadive Ridge. [2] The irregularities of the borders of colonial administration should not determine who rules offshore islands.  [1] Both distances taken from google search.  [2] Whitmarsh, Robert B., ‘Some aspects of plate tectonics in the Arabian Sea’, deepseadrilling.org, p.527,  Incidentally this would potentially matter if the Chagos islands were uninhabited as the Maldives might have a claim due to territorial contiguity