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 per year, to be phased in incrementally over a period of 99 years.

Diego Garcia has played a crucial role in ensuring the security of the UK and its allies across the Middle East, East Africa, and South Asia for more than 50 years. The widespread interest and legal necessity of the deal is due to the strategic position of the Diego Garcia military base, which provides essential tools such as deep-water port, airfield, and advanced communications and surveillance capabilities, allowing the UK to intercept foreign threats such as terrorists from invading the UK.

The roots of the Diego Garcia controversy go back to 1965, when the establishment of the British Indian Ocean Territory (BIOT) saw the military base under the full administrative control of the UK. The BIOT was cleared of its native population and encompasses 640,000 square kilometers of ocean although the land area is only 60 square kilometers, with Diego Garcia being the largest of the islands. Between the years of 1968 to 1973, the UK forcibly displaced the local population, known as Chagossians or Ilois, in order to establish the military base, with many of its inhabitants resettled in Mauritius, the Seychelles, and the UK. The UK Commissioner created legislation that made it unlawful for individuals to enter or remain in the BIOT without a license, officially severing the ties that Chagossians had to their home.

The British government organized compensation agreements for the Chagossians in the 1970s, with around 650,000 pounds allocated to Mauritius to ease the resettlement efforts and an additional 4 million pounds in the form of a trust fund to Mauritius and Chagossian representatives in the 1980s. Although the UK has apologized and expressed regret regarding the manner in which Chagossians were displaced, with both British courts and the European Court of Human Rights confirming that compensation had been paid in full, Chagossians have still criticized the government for diminishing their voices by excluding them from the decision-making process.

The BIOT allowed a formal agreement to be signed between both the UK and the US one year later to fulfill the national military needs of both countries. The UK announced in October that it was conceding its claim to sovereignty over the Chagos Islands to Mauritius in a highly anticipated landmark move. However, the process of finalizing the deal was long and tedious, coming after 11 rounds of negotiations with the previous government. In 2019, the International Court of Justice issued an Advisory Opinion where it stressed that the UK’s control over the Chagos Islands ran contrary to the right to self-determination, and the decolonization of Mauritius was still incomplete under international law. Although this deal aims to return this right back to Mauritius, its lasting impacts remain to be seen.