The Foreign Office has called on China to allow UN observers ‘immediate and unfettered’ access to China’s Xinjiang Uyghur autonomous region, after two leaks provided further evidence of mass arbitrary detentions. An estimated 1 to 3 million Muslim Uyghurs and other ethnic minorities are detained without charge in ‘political re-education’ camps. US media published 400+ pages of documents detailing widespread involvement of senior Chinese officials in these unprecedented mass detentions, where authorities use a scoring system to determine who can leave the camps. Also, the behaviour of relatives outside the camps can affect detainees’ chances of release. More documents were leaked by investigative journalists, similarly detailing mechanisms, guidelines and procedures behind the detentions in Xinjiang and the severity of conditions inside the camps. China claims that the camps are voluntary training centres to combat terrorism.