Diego Garcia, a remote island in the Indian Ocean, is a paradise of lush vegetation and white-sand beaches, surrounded by crystal blue waters.

But this is no tourist destination. It is strictly out of bounds to most civilians - the site of a highly secretive UK-US military base shrouded for decades in rumour and mystery.

The island, which is administered from London, is at the centre of a long-running territorial dispute between the UK and Mauritius, and negotiations have ramped up in recent weeks.

The BBC gained unprecedented access to the island earlier this month.

But there are also clues pointing to its brutal past.

When the UK took control of the Chagos Islands - Diego Garcia is the southernmost - from former British colony Mauritius, it sought to rapidly evict its population of more than 1,000 people to make way for the military base.

Enslaved people were brought to the Chagos Islands from Madagascar and Mozambique to work on coconut plantations under French and British rule. In the following centuries, they developed their own language, music and culture.

In 1967, the eviction of all residents from the Chagos islands began. Dogs, including pets, were rounded up and killed. Chagossians have described being herded onto cargo ships and taken to Mauritius or the Seychelles.

The UK granted citizenship to some Chagossians in 2002, and many of them came to live in the UK.

In testimony given to the International Court of Justice years later, Chagossian Liseby Elysé said people on the archipelago had lived a “happy life” that “did not lack anything” before the expulsions.

“One day the administrator told us that we had to leave our island, leave our houses and go away. All persons were unhappy. But we had no choice. They did not give us any reason,” she said. “Nobody would like to be uprooted from the island where he was born, to be uprooted like animals.”

Chagossians have fought for years to return to the land.

Mauritius, which won independence from the UK in 1968, maintains that the islands are its own and the United Nations’ highest court has ruled, in an advisory opinion, that the UK’s administration of the territory is “unlawful” and must end.

It said the Chagos Islands should be handed over to Mauritius in order to complete the UK’s “decolonisation”.