The BBC has new evidence that China is building a vast network of internment camps for its Muslim population in the western region of Xinjiang. Experts say one facility we’ve identified could be one of the biggest detention centres in the world.

It's thought as many as a million Muslims from the Uighur community are being held without trial in Xinjiang. China denies the claims, saying it has a programme of “vocational training centres” - needed to combat the threat of terrorism.

But the BBC has seen analysis that suggests the number of secure, prison-like facilities in the area has more than doubled in the past two years.

Accounts of life for individuals inside these places tell of abuse and humiliation. Our China correspondent John Sudworth reports from a part of the country where journalists are often prevented from filming.