The inhabitants of this Indian Ocean paradise were involuntarily moved to make way for a US/UK Cold War military base; a truly ugly untold episode of that convoluted conflict.
Writer/director Adrian Jackson tells the story in both wide angle and close up. Between historical scenes in the Pentagon, London private members' clubs and courtrooms, we follow the journey of a modern-day Man Friday, Prosper, whose mother was among the original evictees.
Jackson's production incorporates a multitude of video clips and all manner of visual trickery, from remote-controlled fish to dancing skeletons, to create a rich tapestry; it's impossible to predict what's coming next and each scene contains something to savour.
He's well served by a cast led by Ansu Kabia as Prosper, Johanna Allitt as the counsellor trying to help him and Alasdair Craig as her conservationist husband who's more interested in the Chagos' unspoilt coral than the human price that was paid to preserve it.
Not everything works – the stereotyping of establishment figures (most glaringly the US military commander who does press-ups as he talks) is somewhat tiresome, while the many humans-treated-as-animals metaphors are over-emphasised.
But nevertheless this is an ambitious telling of an important story which adds yet further stain to the Special Relationship. I look forward to the final installment of the Citizens' trilogy, which is due in two years' time.