But critics say they are used to indoctrinate Uyghurs and other minority ethnic groups with the goal of transforming them into devotees of the Chinese Communist party.

In 2019, a six-year-old girl in south London found a message that was apparently from a prisoner in Shanghai in a box of Tesco Christmas cards.

In Xinjiang, the majority of prison labour happens in the agricultural sector, including cotton planting, harvesting and ginning, according to evidence submitted by Laura Murphy and Nyrola Elimä, researchers at Sheffield Hallam University, to the UN.

The programmes work by identifying unemployed people in rural areas and transferring them to farms or factories in different locations where there is a need for workers.

According to a report published by the UN’s human rights chief last year, “the close link between the labour schemes and the counter-‘extremism’ framework, including the VETC [Vocational Education and Training Centre] system, raises concerns in terms of the extent to which such programmes can be considered fully voluntary”.

Journalists who have visited the region have found that many of the facilities appeared to be closed, but there are concerns the detainees have been transferred into the formal prison system rather than being released.

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