Mr Liu, now 34, is in the mould of professional revolutionaries from the age of Bakunin, Lenin, and a youthful Deng Xiaoping.

His dedicated opposition to the Government reportedly led him to organise protests and strikes in some notorious prisons.

Mr Liu smuggled a letter out of the Lingyuan penal colony in Liaoning prison detailing his resistance.

He reportedly organised several hunger strikes and took the lead among new arrivals in refusing to memorise the prison rules. For this he was beaten, tortured and shackled.

Guards put nine-kilogram weights on his legs, assaulted his private parts with a high voltage electric baton, starved him and put him in solitary confinement, according to Human Rights Watch/Asia.

Like many Communist Party leaders, including Jiang Zemin, he became politicised by participating in relatively minor student protests as an undergraduate. In 1985, he joined protests at Beijing University against what was called Japan's new economic invasion of China.

He was caught and warned for putting up a poster protesting over government corruption.

The next year he took part in another protest after police in Shanghai beat a student for dancing with a foreigner at a Chinese-only dance. Then, in 1987, he defied authorities by putting himself up as a candidate in 'elections' for the local people's congress and won.

As a physicist at Beijing University, he worked in the same faculty with physics professor Li Shuxian, the wife of astrophysicist Fang Lizhi who became a student hero during the 1986-87 pro-democracy demonstrations.

Professor Li described him as a 'quixotic and lovable young man'. In 1988, Mr Liu became a pivotal figure in organising the democracy 'lawn saloons' at Beijing University. Professor Fang and his wife were among the speakers.

During the Tiananmen movement after Mr Liu had left university with a physics master's degree, he was an associate of the so-called 'Black Hands', the men whom the party accused of being behind the massive protests. He knew Wang Juntao and Chen Ziming at whose Beijing Social and Economic Sciences Research Institute he worked.

The party believes he helped co-ordinate the student movement.

He was captured while on the run in Baoding, Hebei province, trying to buy a railway ticket. According to one report, local residents turned him in because although he wore workers' clothes, his hands were not calloused.

His detention was shown on national television news. At his trial, he did not hesitate to tell the judge he would have liked to overthrow the 'corrupt Government' but he denied vehemently he had conspired to do so. He swore his prison 'confession' had only been extracted by force.

In May 1990, Mr Liu was reportedly moved to solitary confinement in Qincheng prison near Beijing as a punishment for trying to organise a prisoners' hunger strike commemorating June 4.

His father, a former policeman, and the rest of the family also had refused to be intimidated and appealed to the international community for help. The party took their move so seriously - the renewal of China's Most Favoured Nation trading status was in doubt last year - that foreign journalists were brought to his new prison in Liaoning to disprove reports of ill-treatment.

Mr Liu is now deprived of his 'political rights' for two years. It seems unlikely he will obey the injunctions not to leave home and not to speak to foreign reporters.