Gao went on to become one of the country’s most respected journalists, famed for her writings on the inner workings and political struggles in the country’s top echelon of power.

Last month, at the age of 71, she was jailed for the third time in her life. On April 17, a Beijing court sentenced her to seven years in prison for leaking state secrets abroad. She allegedly passed an internal Communist Party memo called Document No 9 on ideological controls to a US-based news website, an accusation she denied.

Few who have met Gao fail to be impressed by her sharp intellect, boldness and courage. Ironically, these are the very qualities that result in her being sent to jail, her friends and associates say.

Wang Dan, a student leader in the 1989 Tiananmen Square pro-democracy movement who Gao tried to persuade to leave the square before the military crackdown on June 4, said: “She knew very well the danger of writing about top leaders but that didn’t make her flinch. And that’s why she has gone to jail for a third time.”

Each arrest has been linked to her influential writings and her efforts to help her country.

The first time came after Gao, at the urging of former People’s Daily chief editor Hu Jiwei, went to Tiananmen Square in May,1989 and tried to persuade the students to leave. The then deputy editor of liberal publication Economics Weekly, Gao helped students draft a declaration stating they would quit the protests as long as the army held back from entering Beijing. She also helped submit the letter to the National People’s Congress but the proposal was ignored and the army opened fire on students late on June 3 and into the early hours of June 4.

On June 3, just hours before the crackdown, Gao was picked up by security agents and locked up for 15 months. For three months, her family heard nothing about her and thought she was dead.

After the crackdown, then Beijing mayor Chen Xitong singled out a pro-reform article by Gao as the “political programme for unrest and rebellion”.

Her second arrest came in 1993, two days before she was to fly to the United States to take up a visiting scholarship at Columbia University. The accusation this time was that she disclosed the content of a speech by then-president Jiang Zemin in her articles for two Hong Kong publications. A year later, she was sentenced to six years in jail for “leaking state secrets”. She says her arrest, which happened a week after China failed to win the right to host the 2000 Olympic Games, was a gesture of protest to the international community.

When she was released in 1999 she was a politically sensitive person and couldn’t work for state media anymore so she started writing for Hong Kong and overseas publications and websites.

Among her most influential output in recent years was an article she wrote in January 2013 in which she reported President Xi Jinping’s lamentation in an internal speech that when the Soviet Union collapsed, “nobody was man enough to stand up and resist”. She concluded that Xi’s priority was not political reform but to restore late leader Mao Zedong’s legitimacy and to uphold the Communist Party’s one-party rule.

“The restoration of the authority and legitimacy Mao Zedong enjoyed at the beginning of the people’s republic are the purpose and the destination of [Xi’s] road to rejuvenation,” she wrote on German broadcaster Deutsche Welle’s Chinese website.

In May 2013, she wrote a commentary on the party’s resistance to Western, “subversive” ideologies as set out in Document No 9 – the document she was later accused of leaking. She concluded that a country run by leaders who lacked modern approach and vision would inevitably fail. Last month, the Beijing court that jailed Gao alleged that she obtained a photocopy of the document from a retired party official and sent an electronic version to US-based website Mingjing, a claim Gao denied.

Ironically, Gao has become the victim of the intensified ideological controls she has reported, political observers say. Gao’s articles have long ensured her a place under the watchful eyes of the authorities but after her release in 1999, her work was largely tolerated -- until recently.

“This has to do with the deteriorating overall environment,” said Hu Ping, an exiled intellectual living in the US.

Hu said Gao’s jailing came amid a wave of crackdowns on liberal intellectuals and party elders, journalists, rights lawyers, NGOs and “big V” celebrity bloggers in the past two years.

Her former colleague Wang Juntao, who was also jailed after the Tiananmen crackdown, said Gao was aware of how dangerous her job was but accepted that this was a price to pay as an independent journalist under a one-party regime.

“Xi Jinping thinks journalists who … hold dissenting views deserve to be suppressed. He thinks they are making trouble for him,” Wang said.

But even her previous two jail terms had not put her off news. She said last year that her time in jail had only spurred her desire to probe more deeply into her country’s affairs.

“You can change mountains and rivers but not a person’s nature - seven years in jail did nothing to dampen my enthusiasm for news,” she said.

Bao Tong, a former senior official purged after the Tiananmen crackdown, said Gao’s alleged crime proved that she was a first-rate journalist.

“She is a competent journalist – she told people what Document No 9 is all about,” he said. “They fear her because they’re afraid of the truth and they regard the truth as their enemy.”

Bao said that by targeting Gao, the authorities are warning all the journalists that if they criticised the government, they too would face harsh consequences.

Wang Dan said by jailing Gao, the authorities wanted to send a message to the world that China was not prepared to go down the road of democracy and openness.

“The message is that we’re iron-fist rule. We’re arresting the leading figures of civil society and making an example of them and don’t try to challenge our rule,” he said.

Although strong-willed and energetic, she has her weak moments – many were astonished by her televised confession in May last year, two weeks after she was detained. She admitted that she “breached the law and endangered national interests” and she was “very wrong”.

The humble words from Gao on state television were most unlike those of the proud woman and respected journalist her friends knew. In her memoir My 4th of June, she wrote that state security agents also tried to extract a confession from her in 1997, but she refused.

Gao later told prosecutors that her confession last year was coerced because of threats made against her son who was initially detained at the same time as her. He was released after Gao’s confession. Friends say she has always felt guilty towards her only child because he dropped out of school soon after her arrest in 1989, when he was 17.

Her stints in prison and the pressure of constantly living under surveillance have taken a toll on her health – she suffers from heart disease, high blood pressure, chronic back pain and a severe skin allergy. Her husband, who long supported her, died six months before she was detained.

Given Gao’s deteriorating health, her family worries that she won’t survive this jail term – she will be 77 when her sentence ends.

According to her memoir, after she was sentenced in 1994, she told the court: “Your sentencing can destroy my health but it can’t destroy my spirit … I believe China’s history will declare me innocent.”

This time, Gao has condemned her sentencing as “shameless”.

In her memoir, published 20 years after the Tiananmen crackdown, she said the Communist regime wanted people “to abandon their souls to become stones in a high wall”, but she would not be cowed.

“There are still countless souls hidden inside the thin and fragile [egg] shells that are independent and irreplaceable, and they are breaking against that firm, high wall,” Gao wrote.

“Twenty years on, I am still like some of those eggs, continuously breaking against that high wall.”