Britain signed an agreement Thursday to hand sovereignty over the contested Chagos Islands to Mauritius, a move the government says ensures the future of a U.S.-U.K. military base that is vital to British security.

The UK has signed a £3.4bn ($4.6bn) deal to hand over sovereignty of the Chagos Islands to Mauritius, while retaining control of a UK-US military base on Diego Garcia - the largest of the islands. Prime Minister Sir Keir Starmer says the 99-year agreement to lease back Diego Garcia will cost the UK £101m a year,

Britain on Thursday agreed to transfer sovereignty of the strategically located Chagos Islands to Mauritius, resolving a long-standing colonial-era dispute. The Indian Ocean archipelago is home to