The governments of Britain and Mauritius have reached a final deal to settle the future of the Chagos Islands but have been barred from signing it by a British judge.

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

The UK on Thursday signed an agreement to hand over the Chagos Islands to Mauritius and lease back the Diego Garcia military base, critical to the UK and the US, for an average of 101 million pounds