The Tribunal's decision determined that the UK's undertaking to return the Chagos Archipelago to Mauritius gives Mauritius an interest in significant decisions that bear upon possible future uses of the archipelago. The result of the Tribunal's decision is that it is now open to the Parties to enter into the negotiations that the Tribunal would have expected prior to the proclamation of the MPA, with a view to achieving a mutually satisfactory arrangement for protecting the marine environment, to the extent necessary under a "sovereignty umbrella".