Thousands of miles from the nearest anything, these islands scattered across all 7 seas from the Antarctic to the tropics are amongst the remotest places on earth. But life here isn't lonesome. They teem with life from huge penguin colonies to the world's richest coral reefs. Because many are so remote they have acted as laboratories of evolution shaping life in unexpected and dramatic ways. Parrot fish that create beaches. Crabs that are big enough to eat coconuts, and a bright blue lizard. These islands all have one thing in common, they are all British overseas territories. Like sanctuaries in this vast ocean, they harbour a wealth of animals and plants - some unique to each island, some in spectacular numbers. Our journey takes us from the tropical islands in the Caribbean to one of the most unspoiled places on the planet, the Chagos Archipelago in the middle of the Indian Ocean.