A group of renowned mainland academics have written to the National People's Congress and the State Council, calling for the abolition of the controversial 'education through labour' system because it is unconstitutional. The 69 academics, including economist Mao Yushi and law professor He Weifang , sent letters to the NPC's Law Committee and the Legislative Office of the State Council yesterday. They are pushing for immediate abolition of the practice, under which police can detain offenders for up to four years without going through any judicial process. Professor Mao, who was condemned as a rightist five decades ago, said the system had inherent flaws: it was not designed to uphold basic human rights and it led to 'wrongful convictions because of a lack of due justice such as representation by a defence lawyer'. The system had become increasingly out of touch with reality because the country had come a long way in 50 years, he said. The education-through-labour regime was introduced by chairman Mao Zedong in 1957 to purge adversaries, so-called rightists and liberal-minded intellectuals for their dissent on social and political issues. But nowadays, the system is often used by local officials to crack down on petitioners seeking to have their grievances heard by higher authorities. The system was at the centre of a heated debate in September after a farmer in Henan province was forced into an education-through-labour camp in Luoyang for two years even though the prosecutor's office cleared him of charges of vandalising public property. Beijing Institute of Technology economics professor Hu Xingdou , who also signed the petition, said the letters reflected a consensus among the 69 signatories and a subsequent consultation with the wider community. 'Without justice, there's no real social stability we can cherish,' Professor Hu said. Professor Hu said the NPC committee and the State Council office were not liable to respond to the petition under the existing legal framework, but the push for a harmonious society had provided a window of opportunity for an overhaul of the system 'as the rule of law is a prerequisite for such vision'. He also said the 1996 public security law had made the education-through-labour system redundant. Professor Mao said the system might still be relevant as a deterrent against some petty crimes, 'but it should at least be amended to make it in line with the law'.