Why are Muslims in China being locked up?

The Chinese authorities say they are schools students attend voluntarily. Human rights groups say hundreds of thousands of Muslims are detained there without trial. So what’s really going on inside the mysterious camps in Xinjiang, the majority Muslim province in the far west of China? BBC China Correspondent John Sudworth and his producer Kathy Long have been attempting to get to the truth of the story for months, studying satellite images and getting as close as they can to the tall walls and barbed wire that surround the camps. Now, for the first time, they’ve been allowed inside.

Producers: Harriet Noble and Alicia Burrell Mixed by Nicolas Raufast Editor: John Shields