“They just want to force them to be Chinese,” adds Peter Irwin, co-executive director of the Network for Uyghur Rights.

Xinjiang is also strategically important to Beijing, as it straddles trade routes linking China to Central Asia, the Middle East and Europe, while holding large reserves of coal, oil and gas. “They see it as an economic engine for the country,” Irwin says.

“The camps became the focus internationally,” says Irwin of the Network for Uyghur Rights. “But prisons were always central to the system.”