From freedom fighter to Manhattan yuppie: Li Lu masters the ways of the West. Portrait by Frank Fournier
"My most vivid memory of those days?" asks Li Lu. "It was the third day of the hunger strike, a very, very hot day. There was a storm coming. The doctors warned us that we had to move, that if we did not, we would breed germs, which the storm would spread all over Beijing. They said it would cause a serious epidemic. By that time, most of us couldn't move anyway, couldn't eat or drink, and the nights were so cold, the emotion was so thick. Every time we tried to move anybody, they'd faint. There were sirens and ambulances everywhere. And I remember thinking, if we can't carry this out, then I'll be a historical criminal for starting an epidemic... When I woke up in hospital, the first thing I asked was, did it rain? 'Yes.' Did people move the hunger strikers? 'Yes.' Did people kill all the germs? 'Yes.'" He closes his eyes and lifts a serene face to heaven. "So it was all right. It was a wonderful thing."

You look with wonder at this placid, blinking, square-faced Chinese guy in his standard-issue T-shirt and chinos, as he sips iced tea with infinite self-possession in the West End Cafe on Broadway, New York City, a couple of blocks from Columbia University, which has been the centre of his life for the last six years. Li Lu, 30, is a mature student and has just graduated with two degrees from the law and business faculties. But he is also, almost incidentally, the exiled hero of Tiananmen Square, where, in 1989, around 10,000 pro-democracy students staged a sit-in for 22 days, from 13 May to 4 June, before the government became exasperated, sent in the tanks and, depending whose figures you believe, set about murdering either 300 or several thousand young demonstrators. They cut them down with gunfire, crushed them beneath caterpillar tracks and simultaneously crushed China's nascent democracy movement for a generation, burying its memory under a slick of propaganda. This makes Li Lu, the survivor who escaped to the West, a figure of importance: for China, for global human rights movements, for the record books of history - and for idealists who think of Columbia's new graduate as a king in exile.

So you look at him, take in his bland features and engaging laugh, and try to imagine his desperate life and the sights his 23-year-old eyes saw in Tiananmen Square. Seven years after the event, he seems the most relaxed man on the planet. His English is super-fluent - he says "gonna" like Cagney and "in a sense" like Michael Ignatieff - but he remains stubbornly un-American. Rock 'n' roll, chewing gum, baseball and babe culture leave him as unmoved as a Ming vase. He finds women undergraduates at Columbia attractive "in a sense", but always imagines himself going back to China to pursue a career in politics and marry (his girlfriend is Chinese, and dates back to Nanking University days). Ask him how Westernised he is, and he'll talk about his approval of the tenets of the Gettysburg Address. He has "never quite adapted" to New York cuisine, "but my girlfriend cooks Chinese food and we eat it every day, except when we have to go to public functions." His studies in Western culture, he says, have carried him with interest from Homer to Freud, "but in terms of dealing with people, I still behave like a good Confucian Chinese when it comes to family relationships and the role of government. Not Chinese in the way the Communists want you to behave..."

He has been fighting a propaganda battle with the Communist authorities ever since the massacre was followed by a sustained bout of nationwide spin-doctoring, as Deng Zhao-Ping and Li Peng tried to persuade a billion Chinese people that the trouble had been caused by a small band of "counter- revolutionaries" who had duped innocent students into revolt and planned to destabilise the country. Did the Chinese people still believe it? "My sense is that they thought well of the students - thought they had good intentions, that they were patriotic, out for the good of their country. But the argument they've had put in their minds is that the students wanted radical reforms that would have resulted in chaos, as in the Soviet Union. And I think they've believed this line over the years."

Li Lu, by contrast, sits there as the embodiment of What Really Happened. He was the man, he suffered, he was there. He's currently embroiled in a row over a new documentary, The Gate of Heavenly Peace, which suggests that a number of the student leaders, including Li Lu and Chai Ling, left hundreds of students to their fate while they themselves got away. The Chinese authorities have tried to ban it, the Chinese samizdat press condemned it, the international bien-pensant community tut-tutted. ("It takes a special gift," commented Richard B Woodward in the Village Voice, "to piss off the Chinese government, and many of their sworn ideological foes among the leaders of the rebellion, and the pillars of the American human rights establishment.")

Li Lu was ten when Mao-Tse Tung died. He remembers it as a national tremor that followed a local one. "It was exactly a month after the huge earthquake of 1976. One day, a loudspeaker announced that there was major news, that everybody must be at a certain place at a certain time; so we all went. And they announced that Mao was dead, and it was unreal because, as a child, as soon as you can speak you learn to say 'Long Life to Chairman Mao'. The idea that he could have died was abhorrent. And it was right after the quake, and people hadn't recovered from the shock; virtually everyone had lost one or two or even all the members of their family, and hadn't had time to cry. So people began to cry - initially for Mao, then all of a sudden they were crying for their relatives who'd died in the earthquake. It was the sound of complete emptiness."

Li Lu's memory hides a personal trauma. His childhood was tough beyond belief. His parents were victims of the Cultural Revolution, denounced as intellectual renegades and sent to "re-education camps" when he was six months old. The baby was shunted around orphanages and foster parents, who didn't wish to be tainted by the child of outcasts. Finally, he was sent to live with a family in a coal-mining community; it was then that the earthquake hit China, killing his entire foster family. Stunned by his lucky escape (he was under the bed the family was sleeping on when they died) he was reunited with his true family when Deng came to power and started his "open-door" policy. But the bruises on his soul were not so easily healed. He learned that there were two realities in modern China - that which is the case and that which the government says is the case.

"I knew life was horrible. I knew it was not exactly as we were taught, about how wonderful life can be. My first experience of this irony was the fact that our elementary school reopened less than 100 days after the earthquake. It was formally reported on central TV news - and I thought, but that's not true, we have no school and no teachers, we just opened the place for half a day so the television could film us. And I began to think, maybe it's the same with everything, maybe everything we're told isn't true."

From this early scepticism, everything else followed. His career as a radical began when, at Nanking University, he took literally the reforming spirit of Hu Yaobang, the enlightened Communist Party chief once thought of as China's Gorbachev, and masterminded the forming of an independent Student's Union. When Hu Yaobang was forced to resign, a network of whispers swept through the campuses from Nanking to Shanghai, demanding the rise of a new leader to preserve the reforming spirit. Then, in April, Hu Yaobang died. "And on the following day," says Li Lu, "in nearly all the major cities of China, people began to mourn him openly and organise various memorial events. They turned into political events and became a large- scale demonstration. It was as simple as that."

After the massacre, he stayed in Beijing, trying to organise a press conference for world reporters. But the government issued a list of 21 wanted students and Li Lu couldn't function any more. What was it like, being on the run? "It's terrible. You don't know where to go. You don't know what's happened. You don't know your destiny. All you know is there's people on street corners trying to see if your face matches the ones on the Most Wanted list." So he went into hiding in the south, escaped to Hong Kong ten weeks later through a network of "friends", about whom he is charmingly vague, and made it to New York. Disorientated, culturally at sea, shell-shocked by the death of so many friends, traumatised by the crushing of his democratic dreams, he found himself in a rambling Victorian brownstone, unable to speak English. He was befriended by a human rights activist called Mary Daly, through whom he met Trudi Styler, also known as Mrs Sting; one more shock for the penniless (and clothes-less) emigre was being brought a bag-load of Sting's cast-off threads to wear. Ms Styler went on to fund the movie based on his memoir of Tiananmen Square, Moving the Mountain. Through such glamorous associations, he met the glam-rock fraternity. Did he enjoy it? "Oh, journalists get the impression I'm moving in high society. It's not true. Yes, Madonna came to the film's premiere and told me she loved the film, had even cried during it. But... " He giggles, as if I'd asked whether he'd managed to remove her top. "She came there for Sting and Trudi. She wasn't very interested in me at all."

He is happier talking in political abstractions, about how China needs "an independent judiciary, rule of law and human rights", as a basis for future change. He disdains all talk of his returning to take power in China ("We're talking about a billion people here; for those billion people to agree on a leader, he must be a remarkable man"), though he foresees a political future there. The big question, of why he is considering a career in investment banking - a shy-making number of New York corporations are vying to put Li Lu's name on their payroll - elicits a smoke screen of guff about liberty, democracy and private ownership: "It may be motivated by self-interest, but through this thing called the market it can generate social welfare." He has, he reveals, been offered a number of jobs - "academic ones, think tanks, law, business" - but concludes, "The general public in China will look up to someone who is economically successful - and, of course, a career in politics requires a lot of money." Thus the eternal student activist, the peruser of all Western culture has to offer, settles for becoming a bread-head: "It combines personal interests and long-term goals..."

Outside the West End Cafe, Li Lu and I stroll uptown in the baking lunchtime heat. He assures me that the subway's dangers are greatly exaggerated, and I leave this newly cosmopolitan executive-class revolutionary to his promising future as a Manhattan banker, with attractive remuneration package and handsome pension scheme. Did he have any other Tiananmen memories that have never gone away? He thinks. "Early in the massacre, there was one man I remember. He was deeply wounded - so covered in blood you couldn't see where the wound was - and he had asked people to carry him back to student HQ to report what was happening. He said, 'Don't move from here. So many people have died on the road fighting for you. Stay here. Don't leave."' You mean, he was saying, sod the generals? Criticising you? "No, no, you must understand the expectations of these people. For the first time in 40 years they had a taste of freedom. They were willing to go, they were willing to sacrifice all they had. All they cared about was that it should continue. This man said, 'There will be more people coming in your defence, there will be soldiers defecting tonight. Stay here - by daylight we're gonna win.' Then the ambulance came. I never forgot him." He shakes his head in the Manhattan sunshine. "These are the things I have brought with me down all these years"