The massacre in which hundreds, perhaps thousands, of people died in Beijing on the night of June 3 and the early hours of June 4 1989 remains the most important and traumatic single event in modern Chinese history.

It was the moment the people’s army turned its guns on the people, shattering the legitimacy of the Communist party and ushering in an era of rapid capitalist-style reforms.

In the aftermath, the Berlin Wall and the Soviet Union both collapsed, China’s education system was overhauled to inculcate greater nationalism and the Communist party established a new contract with its subjects: making a fortune is allowed but politics is off-limits.

Despite the party’s attempts to expunge the events from the record, the scars remain in the collective consciousness of its subjects. For the idealistic student leaders who gathered in Tiananmen Square to face down the ageing autocrats, the trauma, guilt and rage from what followed has haunted them ever since.

“These students were called on to the global stage as very young people but many were not ready for it and they still feel an immense pressure and responsibility for what China could have been and what it is now,” says Perry Link, a professor at University of California at Riverside, who co-edited the Tiananmen Papers.

Almost none of the student leaders have been allowed to return to China, even to attend funerals or visit ageing parents, rendering them irrelevant in their native country and adrift in the places where they sought refuge.

“These young people were taken out of their ecology and deprived of oxygen,” says Orville Schell, director of the Center on US-China Relations at the Asia Society, who was also in Beijing in 1989. “You’d have to say the party’s strategy of exporting people like them has proven to be a smart one.”

Today’s regime is a direct successor to the one that ordered the massacre and many senior leaders, if not involved directly themselves, were beneficiaries of the decision.

Many of the early protest leaders, such as Wang Dan and Wuer Kaixi, remain committed to their original cause and ideals. Chai Ling, the “supreme commander” of the square, and Li Lu, her “deputy”, who both joined the movement in its later stages have reinvented themselves.

If the former student leaders were allowed to return they would not recognise the symbols of materialism, wealth and power built up by 25 years of continued, relatively stable, Communist party rule. But the party’s persistent repression of dissent, ideas and memory would probably feel quite familiar.

Wuer Kaixi: ‘‘I do not regret my actions but the price was enormous’

The sight of hunger-strike leader Wuer Kaixi in hospital pyjamas scolding and rudely interrupting the premier of China on national television in May 1989 electrified student protesters gathered outside in the square.

Many participants and scholars who have studied the Tiananmen movement believe this display of arrogance and disrespect was the final straw for Communist party hardliners.

On May 20, two days after the confrontation, Premier Li Peng, who would later be labelled the “butcher of Beijing” for his role in ordering the massacre, declared martial law. Reformist party head Zhao Ziyang was placed under house arrest, where he would remain until his death in 2005. Two weeks after that, the tanks rolled in and crushed the movement completely.

When the government published names and grainy photos of the most wanted student leaders in the aftermath, Wuer Kaixi, then just 21 years old and studying education at Beijing Normal University, was number two on the list.

“I was told the People’s Liberation Army had been given a secret order not to capture Wuer Kaixi alive so I decided to leave Beijing,” the 46-year-old Wuer Kaixi says.

With the help of ordinary citizens, gangsters and smugglers, he was spirited to the then British colony of Hong Kong and eventually on to the US, where he studied for a year at Harvard before moving to Dominican University in San Francisco.

He has lived in Taiwan, since the mid-1990s. Looking back, Wuer Kaixi, a member of the Uighur ethnic minority blamed by Beijing for a series of recent terrorist attacks, is acutely aware of the significance of the movement he helped lead a quarter of a century ago.

“This was one of the greatest and most powerful movements in history,” he says. “It marked the end of the cold war and the demise of communist totalitarianism and it was a turning point for China.”

He was a key organiser of the first major student march in April 1989 and of the mass hunger strike that drew sympathy from across the country and the world.

But he was ousted from the student leadership in the final days before the massacre because he advocated leaving the square and was seen as insufficiently radical.

To this day, unlike some of his contemporaries, he remains a determined advocate of political reform in China.

“I have decided to remain a democracy activist and dissident for many different reasons but survivors’ guilt is one of the most important,” he says. “What we did was a brave and honourable thing and I do not regret my actions but the price was enormous for many people, including myself.”

Chai Ling: ‘China will definitely have democracy in the future’

Chai Ling talks to the students in Tiananmen Square, and today

In late May 1989, as the protests centred on Tiananmen Square were drawing to their bloody end, an unlikely figure emerged as “supreme commander” of the Chinese student democracy movement.

With her frail frame and Joan of Arc fervour, Chai Ling, a 23-year-old psychology student, became the symbol of the revolution that transfixed the world.

“Back then a journalist asked us if we wanted democracy,” Ms Chai said in an interview from her home in the US last week. “We really didn’t know what that was, we just thought it was very good so we set up our own fledgling democracy there in the square.

Ms Chai is probably the most contentious figure to emerge from the wreckage of the uprising that rocked the Communist party and altered the course of modern Chinese history.

In a rambling and highly emotional interview just days before the massacre, she made statements that still anger many in the Chinese dissident community.

“The next step – as for myself, I want to continue living. As for the students in the square, I think the only thing they can do is persist to the end and wait for the government to become so desperate that it starts a bloodbath,” she said then.

Her comments should probably be taken in the context of the extreme stress she was under, having just been told she was on a government hit list and as troops gathered on the outskirts of Beijing.

She says the criticism, guilt and depression have disappeared since she found Jesus in 2009.

The fervour of her religious conviction is reminiscent of the fiery spirit that led a revolution and saw her stay until the very end, when the tanks and combat units were assaulting the square.

The several thousand diehard students who remained eventually decided to leave in the early hours of June 4.

Chai Ling led the way, in a withdrawal partly negotiated with authorities by Liu Xiaobo, the Chinese Nobel Peace Prize winner currently serving 11 years in prison for advocating peaceful political reform in China.

With the help of Operation Yellow Bird, Ms Chai managed to flee through Hong Kong to France and on to a scholarship at Princeton University in the US.

She has been a devout Buddhist, a businesswoman, an activist and a philanthropist but she has never returned to China.

To her the country is a modern-day Sodom and Gomorrah where people are interested only in money and the pleasures of the flesh.

“China will definitely have democracy in the future but it will be better than democracy, it will be like heaven,” she says. “All our tears will be dried. There will be no death or unhappiness.” Additional reporting by Gu Yu

Wang Dan: ‘Sooner or later the young generation will stand up to fight’

Wang Dan’s Google Plus profile speaks volumes. He dropped out from Peking University, finished “advanced studies” at three Chinese prisons, and obtained a PhD in history from Harvard University.

Twenty-five years ago, he was a freshman history student at Peking University who held “democracy salons” and edited a magazine. But he was catapulted to fame as images of him leading a hunger strike in Tiananmen Square flashed across television screens around the world.

He topped the Communist party’s blacklist after the crackdown, went on the run but was soon captured. He spent most of his twenties in prison, before release on medical parole in 1998 ahead of a visit to China by President Bill Clinton.

More than two decades since his baby-face became a symbol of the Tiananmen protests, Mr Wang is still proud of the movement that placed the dark side of the Communist party in the global spotlight.

“I am really, really proud of my fellow Chinese citizens because at that time so many people stood up for democracy,” he says from Taiwan, where he teaches history. He cannot return to China but as he watches from afar – splitting his time between Taipei and Los Angeles – he is pessimistic about political reform under the new Chinese president.

“Xi Jinping is going to be more conservative in terms of politics, maybe more than Hu Jintao,” he says. “It is very obvious from everything you can see before the 25th anniversary as many people were arrested.”

He is more optimistic about the desire of young Chinese to learn the truth of 1989 – a taboo in China – from what he hears from his mainland students in Taiwan. “Many of them are eager to know the truth . . . what happened 25 years ago,” he says, explaining that when they arrive in Taiwan, many go straight to Facebook, which is banned in China, to learn about Tiananmen. “They still have curiosity and are eager to know, that is very important.”

But he thinks the current generation will fight differently – using the internet as a potent tool – and for a slightly different cause than the protesters who filled Tiananmen Square in 1989.

“Our generation fight for the benefit of the country or the state. Democracy for us is for China,” says Mr Wang. “For the young generation, the post-90s generation, sooner or later they will stand up to fight, but maybe fight for their own benefit, for the freedom of themselves.” Demetri Sevastopulo

Li Lu: ‘We became entrepreneurs instead of working for government’

The only person Charlie Munger ever trusted with his family’s money was once one of China’s most wanted fugitives.

The vice-chairman of Warren Buffett’s Berkshire Hathaway met Li Lu, a Tiananmen Square student leader, after he had fled China and obtained his undergraduate, business and law degrees from Columbia University – all three in 1996.

After a brief stint with investment bank Donaldson, Lufkin & Jenrette, Mr Li started his own firm. Introduced by mutual friends, Mr Munger was impressed by the young man’s “ferocious” intelligence.

“I said, for the only time in my life, ‘I’ll give you Munger money to manage’,” Mr Munger recalled. “I’ve never done it before and I’ve never done it since. It has been a wonderful investment.”

While at Columbia, Mr Li attended a talk by Mr Buffett that convinced him his future lay in finance. “Because of the tragedy of Tiananmen Square, my generation became entrepreneurs instead of working for the government,” he said during a 2012 address at his alma mater. “Today, all of the major private companies in China are led or funded by people of my generation. It is the greatest generation of entrepreneurism.”

Mr Li is most famous for his punt on BYD, the Chinese battery and electric carmaker. Although BYD is now struggling, with first-quarter sales down 30 per cent, his initial investment of about $40m in the company is worth more than $280m.

His fund is BYD’s second-largest investor, with 7 per cent, behind Mr Buffett’s MidAmerican Energy Holdings, with 28 per cent. Mr Munger said the investment in Mr Li’s fund had returned “hundreds of per cent”.

In the early 1990s, Mr Li’s charm and facility for English, a language he did not speak before arriving in the US, quickly made him a star on the human rights circuit, especially during the then annual debate over whether imports from China should be subject to punitive tariffs because of Tiananmen.

Mr Li now rarely talks about Tiananmen, and declined an interview request. To do so could jeopardise his investment activities in China, which he visits regularly.

“You’d think with his revolutionary background that [Li] would have some old-fashioned hatreds,” Mr Munger said. “On the contrary, he is terribly impressed by modern China. I would say he’s a loyal American and a loyal Chinese, but he’s very much a capitalist now. He doesn’t have a revolutionary bone in his body left.” Tom Mitchell

How Operation Yellow Bird helped 800 dissidents flee

The rescue of Tiananmen Square student leaders began just days after the tanks rolled in and the government published its most wanted list of “counter-revolutionaries”.

It was called Operation Yellow Bird after a Chinese proverb: “The mantis stalks the cicada, unaware of the yellow bird behind.” Its goal was to smuggle prominent members of the movement to safety in the west.

The operation was extremely successful. It brought together an unlikely mix of ordinary Chinese citizens, sympathetic Communist officials, Hong Kong activists, western intelligence agencies, diplomats and Hong Kong triad gangsters.

Of the 21 leaders on the most-wanted list, 15, including Wuer Kaixi, Li Lu, Chai Ling and Feng Congde, her then husband, were spirited out of China to Hong Kong, given false identities, passports and disguises and sent abroad. In total, 800 escaped.

Many went first to France, but most travelled on to the US for scholarships at Ivy League universities.

The extraction missions, aided by MI6, the UK’s Secret Intelligence Service, and the CIA, according to many accounts, had scrambler devices, infrared signallers, night-vision goggles and weapons.

Sympathisers helped student leaders travel more than 2,000km from Beijing to the Hong Kong border by bus, boat, train, car, donkey cart and in storage tanks.

Many were sheltered for months before smugglers and “snakehead” human traffickers, many of them paid handsomely, took them to Hong Kong.

After nearly 10 months on the run, Chai Ling arrived in Hong Kong in a cargo box full of rotting fish, while the rescue of Wuer Kaixi failed twice before he escaped.

The average cost was HK$50,000-100,000 – double the usual price to smuggle people out of China because of the extra risk. For Wuer Kaixi it was about HK$600,000.

The money came from businesspeople, mob bosses, donations and foreign governments. The British colonial government helped with continued extractions of dissidents up until the handover in 1997, when Hong Kong returned to Chinese rule and all records of the operation were removed from the territory.