Blind Chinese activist Chen Guangcheng, the "barefoot lawyer" who left Saturday for the US after escaping house arrest, gained worldwide acclaim for exposing abuses under the "one-child" policy.

Blinded by an illness in his infancy, Chen, 40, grew up in China's eastern province of Shandong on classical Chinese tales of courageous heroes who fought wicked officials to help powerless ordinary people.

The stories, told to him by his father, inspired Chen to help others and to embark on his civil rights crusade, his brother Chen Guangfu once told AFP.

But his efforts at improving human rights in China mired him in a deepening abyss of abuse stemming from police beatings, round-the-clock surveillance, numerous detentions and finally jail.

After accusing authorities in Shandong's Linyi county of forcing up to 7,000 women to undergo late-term abortions or sterilisations under the "one-child" policy, Chen was sentenced to four years and three months in prison in 2006.

Officially, Chen was convicted of "wilfully damaging public property and organising a mob to disturb traffic", referring to a rally by his supporters protesting against the government's treatment of the blind lawyer.

During his trial, his lawyers, who had already suffered repeated beatings by thugs believed to be hired by local authorities, were refused entry into the courtroom.

While in prison, he was beaten by fellow inmates on at least one occasion, according to the Chinese Human Rights Defenders, a network of rights activists.

His wife, Yuan Weijing, was reportedly subjected to harassment by officials and physical violence.

After his release in September 2010, Chen and his family were held under house arrest, effectively cut off from the outside world, with dozens of security officers posted outside their home.

Activists and journalists who tried to visit him were roughed up or harassed and barred from gaining access to the village, among them Hollywood actor Christian Bale, who travelled there last December.

Chen and his wife were also severely beaten after they smuggled out a videotape of themselves documenting the conditions of their house arrest last year, the US-based ChinaAid rights group said at the time.

Chen, who has no formal legal qualifications, is what is known in China as a "barefoot", or self-taught, lawyer.

After pursuing law at a blind school during his youth, Chen armed himself with legal knowledge and began giving free legal advice to villagers for all sorts of problems, according to his brother.

He gained fame in his locality for helping people sue officials over a wide variety of injustices, with corrupt officials in government a particular target.

Although the State Family Planning Commission in 2005 publicly admitted that local officials in Linyi had carried out forced abortions and sterilisations and vowed to bring perpetrators to justice, pressure on Chen from county authorities never abated.

In 2006, he was named by US-based Time magazine as one of the world's 100 most influential people for his courage in exposing rights abuses in China.

Chen is a past recipient of the Ramon Magsaysay Award, a human rights prize awarded to deserving activists in Asia.

His fleeing from house arrest in April this year to the US embassy in Beijing became a major diplomatic wrangle between the world's two biggest economies.