The first evidence that China was imprisoning vast swathes of its Uighur Muslim population in its northwestern province of Xinjiang began seeping out last year.

Such was the secrecy surrounding the project that it took detailed research on Google Earth for evidence of the internment camps to emerge. In such remote corners of the world, it can take the service months or even years to update its satellite photos, prolonging global ignorance of what was happening to the Uighur people.

The Uighurs are an ethnic and religious minority who have long been subjected to repression and ill treatment by Beijing’s ethnic Han Chinese majority one-party state.

The name of the province where they live, Xinjiang, means New Frontier in Han Chinese, reflecting their centuries-old separation