Horrors of life in China labour camp
Chinese police are allowed to send anyone to prison for up to four years, without a trial and with little chance of appeal.
Petty criminals and dissidents across China have been locked up in "re-education through labour" camps since the 1950s, but now Beijing says it is going to abolish the controversial detention centres.
The BBC's Martin Patience has been speaking to one former inmate, Liu Hua, who was released last year.