It's one of the most criticised elements of China's justice system. The Re-education Through Labour (RTL) camps were introduced in 1958 under the regime of Mao Zedong and continue to be used this day. 2,000 people are currently known to be held inside them. They're controversial because prisoners can be sent there for up to 3 years without trial. In recent months, the Chinese government has been forced to promise it will look into reforming the system.