The UK has called on China to give UN observers “immediate and unfettered access” to detention camps where up to a million Uighur Muslims are being held.

It comes after leaked Communist Party documents showed how Uighurs and other ethnic minorities are cut off from their families and subjected to systematic brainwashing at camps in Xinjiang.

The official files, leaked to the International Consortium of Investigative Journalists, also show how suspects are identified – often before they have committed a crime – through a digital mass surveillance programme.

They are then incarcerated under strict rules, with a memo from Xinjiang’s top security chief explaining how to prevent escapes, maintain security about the camps’ existence and how to monitor and control various aspects of the detainee’s lives.

Responding to the release of the documents, the Foreign Office said it had “serious concerns about the human rights situation in Xinjiang and the Chinese government’s escalating crackdown, in particular the extra-judicial detention of over a million Uighur Muslims and other ethnic minorities”.

China destroying Uighur burial grounds Show all 6 1 /6 China destroying Uighur burial grounds China destroying Uighur burial grounds Teywizim cemetery in Hotan (before and after) China is destroying burial grounds where generations of Uighur families have been laid to rest, leaving behind human bones and broken tombs in what activists call an effort to eradicate the ethnic group's identity Earthrise/AFP/Getty China destroying Uighur burial grounds A cemetery in Xayar (before and after) This combo of satellite images received on September 30, 2019 from CNES 2019, distributed by Airbus DS and produced by Earthrise shows a picture from August 29, 2017 (top) showing a cemetery (C) and the same view on July 5, 2019 (bottom) with no sign of the facility in Xayar, Xinjiang province. - China is destroying burial grounds where generations of Uighur families have been laid to rest, leaving behind human bones and broken tombs in what activists call an effort to eradicate the ethnic group's identity in Xinjiang. (Photo by Handout / various sources / AFP) / TO GO WITH China-rights-Xinjiang,FEATURE by Eva Xiao, Pak Yiu, with Andrew Beatty -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / CNES 2019/ DISTRIBUTION AIRBUS DS/ PRODUCED BY EARTHRISE" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVES / (Photo by HANDOUT/EARTHRISE/AFP via Getty Images) HANDOUT Earthrise/AFP/Getty China destroying Uighur burial grounds A graveyard in Aksu (before and after) An image of a graveyard in Aksu in 2015, where Uighur poet Lutpulla Mutellip was buried and the same view in 2018 and then again in 2019 showing a new park called "Happiness Park" Earthrise/AFP/Getty China destroying Uighur burial grounds A cemetery in Xayar (before and after) This combo of satellite images received on September 30, 2019 from CNES 2019, distributed by Airbus DS and produced by Earthrise shows a picture from August 29, 2017 (top) showing a cemetery (C) and the same view on July 5, 2019 with no sign of the facility in Xayar, Xinjiang province. - China is destroying burial grounds where generations of Uighur families have been laid to rest, leaving behind human bones and broken tombs in what activists call an effort to eradicate the ethnic group's identity in Xinjiang. (Photo by Handout / various sources / AFP) / TO GO WITH China-rights-Xinjiang,FEATURE by Eva Xiao, Pak Yiu, with Andrew Beatty -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / CNES 2019/ DISTRIBUTION AIRBUS DS/ PRODUCED BY EARTHRISE" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVES / (Photo by HANDOUT/EARTHRISE/AFP via Getty Images) HANDOUT Earthrise/AFP/Getty China destroying Uighur burial grounds Sulanim cemetery in Hotan (before and after) This combo of satellite images received on September 30, 2019 from CNES 2019, distributed by Airbus DS and produced by Earthrise shows a picture from April 24, 2018 (top) showing the Sulanim cemetery (C) in Hotan, Xinjiang province and the same view on August 6, 2019 (bottom) with no sign of the facility and it has been replaced with a car park. - China is destroying burial grounds where generations of Uighur families have been laid to rest, leaving behind human bones and broken tombs in what activists call an effort to eradicate the ethnic group's identity in Xinjiang. (Photo by Handout / various sources / AFP) / TO GO WITH China-rights-Xinjiang,FEATURE by Eva Xiao, Pak Yiu, with Andrew Beatty -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / CNES 2019/ DISTRIBUTION AIRBUS DS/ PRODUCED BY EARTHRISE" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVES / (Photo by HANDOUT/EARTHRISE/AFP via Getty Images) HANDOUT Earthrise/AFP/Getty China destroying Uighur burial grounds A cemetery in Xayar (before and after) This combo of satellite images received on September 30, 2019 from CNES 2019, distributed by Airbus DS and produced by Earthrise shows a picture from August 20, 2014 (top) showing a cemetery (centre L) and the same view (bottom) on July 5, 2019 where it has been replaced with a a newly built standardised cemetery, in Xayar, Xinjiang province. - China is destroying burial grounds where generations of Uighur families have been laid to rest, leaving behind human bones and broken tombs in what activists call an effort to eradicate the ethnic group's identity in Xinjiang. (Photo by Handout / various sources / AFP) / TO GO WITH China-rights-Xinjiang,FEATURE by Eva Xiao, Pak Yiu, with Andrew Beatty -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / CNES 2019/ DISTRIBUTION AIRBUS DS/ PRODUCED BY EARTHRISE" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVES / (Photo by HANDOUT/EARTHRISE/AFP via Getty Images) HANDOUT Earthrise/AFP/Getty

A spokesperson said: “We want to see an end to the indiscriminate and disproportionate restrictions on the cultural and religious freedoms of Uighur Muslims and other ethnic minorities in Xinjiang.

“The UK continues to call on China to allow UN observers immediate and unfettered access to the region.”

Earlier this year, the UK led 22 other countries at the UN in issuing a joint statement condemning China’s detention of Muslims.

Other signatories included Australia, Canada, France, Germany and Japan.

The leaked Chinese government documents also lay out strict rules for what it claimed were “vocational education and training centres” in Xinjiang.

It says: “The students should have a fixed bed position, fixed queue position, fixed classroom seat, and fixed station during skills work, and it is strictly forbidden for this to be changed.

“Implement behavioural norms and discipline requirements for getting up, roll call, washing, going to the toilet, organising and housekeeping, eating, studying, sleeping, closing the door and so forth.”

The documents appear to support testimony from former detainees as well as satellite imagery.