NEW YORK: 4 Jan

After getting the home phone numbers of the student leaders from the Internet, I spent two weeks trudging through sub-zero temperatures, seeking them out.

Tang Boquiao lives in a suburb of Queens. He organised a demonstration of 500,000 in a railway station in Hunan two days after the Beijing massacre, was imprisoned, tortured for two years and thrown out after four years in prison. A mild and serious man snuffling with flu. BBC tape recorder dies as he describes his imprisonment making designer label shirts in a Chinese jail. He gives me numbers of activist friends in China and tells me on no account to mention his name if I call.

Visit producers in the Warner Brothers building who want to premiere my play, Catalogue of Misunderstanding, there this autumn. Meet the people who run Human Rights in China, an organisation that comprises a floor of the Empire State Building.

The square at the height of the protest

Go back next day to sit in empty offices on a Saturday morning and speak with Bao Pu as Manhattan is lost in white swirl outside. His father was a member of the Chinese central committee and the only one who voted against the use of violence in June 1989. A choice that endangered his family, ended his reforming career and put him in prison for eight years. Will you tell my father's story asks Bao Pu?

On Sunday I trace Lu Jing Hua to a tiny apartment in Brooklyn. She crossed Tiananmen Square each day by bicycle on her way to work in a dress shop, then she stopped to listen to speeches, came back the next day with a banner and by default found herself the leader/founder of the massive Beijing Workers Federation. Forced to flee the country a month later, leaving her new born baby. She re-enacts confrontations with soldiers trying to persuade them to not use their guns on the students. Now remarried to an American peace movement activist, she works in a local shop.

In a restaurant on Upper Broadway I spend Sunday evening with Xin Ku, a student who left a sports match at a regional university to go to a meeting to support the hunger strikers, made a collection, was elected leader, sent on the train to Beijing that night, became part of the leadership in the square and fled the country later, all in the same sports gear.

He tells me how he negotiated with the tank commander and got the last couple of thousand students out of the square, the night the tanks moved in.

Student leader Wang Dan, during the protests

At Columbia, Wang Juntaio and I share an umbrella against the blizzard as he explains how he tried to mediate for the students with the government but the students were incapable of any consensus, and how he then arranged transport for the leaders' escape as the army moved in.

A veteran of the 1978 Democracy Wall movement, he tells how everyone wants always to ask about June 1989. He turned down the publishing and movie deal for his life story. "I've moved on now," he says as we reach his postgrad apartment where student journalists are waiting to interview him about Tiananmen Square.

At Boston I get off the train into air temperature minus nine. Here to spend the evening with Wang Dan, number one most wanted student.

Lunch with Shen Tong who had the privilege of a place at university before June 1989 and watched the events in the Square from the window of his parents' government apartment nearby. He is just completing a degree in PR and takes me to the Harvard book store where I buy a copy of his autobiography.

My plan is to fly back to New York that night, so I go to get a plane ticket but my BBC expenses don't stretch and my credit card is declined, which means I have to get the train and I'll only have half an hour with Wang Dan.

Now in his early 30s, Wang Dan still looks like a lost adolescent and it is difficult to recognise that this is the bravest of the student leaders, who refused to flee and spent four years in prison before being sent into exile. Casually, I ask what I should do in Beijing, spreading out a map of the city he cannot visit. "Stage a hunger strike in Tiananmen Square," he replies without blinking.

For the 10th anniversary Wang Dan is masterminding a petition to the Chinese government of one million signatures demanding democracy in China.

LONDON

Jetlagged lunch with Kate Valentine, the producer who dreamed this up. Swap the tape recorder for mini-disc player to record the street sounds of Beijing on location. Kate briefs me for China, I am not say to anyone why I am there because it's forbidden to discuss the events of 1989 there. So I go round the corner to the Chinese Embassy to get a tourist visa and hand over my passport. That night my wallet is stolen on the Central Line with the receipt from the Embassy. One day later, after some sweet talking at the visa section, I am on the plane to Beijing.

BEIJING

The degree of normalcy in Beijing is astounding. Check into the Holiday Inn quarter of a mile from Tiananmen Square, still lagged from New York.

Walk the streets all day and barely see another westerner apart from lines of tourists descending from coaches. The temperatures here are sub zero (as New York) but a curiously dry environment renders me thirsty all the time and creates little snow.

On first impression, an unexpectedly easy city to operate in. Signs in English and Chinese, with a bi-lingual map, it's possible to get into taxis and point to show where you want to go.

It's the week Starbucks and Ikea open in Beijing.

Ate dumplings sold by women with steaming dim-sum barrows, and each night visit the night food market where all the hundreds of these barrows converge after dark. People stand in the sub-zero temperatures slurping noodles and every imaginable variety of Chinese food. Stall holders amused at my presence as a rare westerner at this venue.

Security stepped up for the annivesary

It is forbidden to discuss the events of 1989 in China, especially with westerners. I decide to lie, I will say to people that I'm writing a play (ficton and therefore not requiring journalist's accreditation) but I will say I haven't decided what it's about yet. If I can't talk to anyone about Tiananmen Square, I can use this trip to learn about the cultural background to the stories I've been told in New York. This decision, to lie to everyone, means any Chinese I meet are protected and I don't break the law.

Realise I'll also have to lie to the British Council too. They are arranging for me to meet theatre practitioners. All the calls to the compound are taped so I have to remember to not mention why I am here on the phone.

Next day I make the first sound recording in a market, and someone follows me so I go back to Holiday Inn and remove all the BBC stickers from the equipment. If I get hauled in I can claim to be an eccentric tourist. These recordings of the street sounds of Beijing will form the backgound to my play when it is broadcast.

Tiananmen Square is fenced off now for "resurfacing " that will take till the 50th Anniversary of the founding of the Peoples' Republic in August, rendering it inaccessible for the 10th anniversary of 4 June 1989. The Square is as big as Trafalgar Square merged with Parliament Square and everything in between demolished.

A party in the diplomatic compound for ex-pats and everyone hits on me, they must be so bored with each other.

I meet the Brits who work as PR apologists for the Chinese government. One introduces the subject of 1989. She says it infuriates her when people raise the subject of human rights because the Chinese Government are really doing their best. Asked why I was in New York last week, I say it was to meet the producers of my play. You'll do fine just as long as you don't write a play about Tiananmen Square she concludes.

At lunch next day, courtesy of the helpful British Council, a theatre practitioner leans across the table to me while our host is at the bathroom. You should write a play about Tiananmen Square she whispers. "I hear you," I reply and nod as our host returns.

BBC introduce me to some students at Beijing University with a passion for democracy and I hang out with them, visit underground pro-democracy publishers, student cafes and participate in debates on the ideal form of democracy held in crowded dorms. The difference between 1989 and now is the lack of militancy, these debates are entirely theoretical. Students now spend too much time doing extra jobs to live, so they have no time to demonstrate.

People spit here in the street the whole time, and then the wind comes from Mongolia and blows the city dust into the air. High incidence of TB and everyone has sore throats including me but I decide to tough it out. Each time I get back to the Holiday Inn I take a shower to wash off the grey chemical-smelling dust that collects on my skin. One night I am unable to sleep for the pain of my throat and at 4am I realise the skin is coming off the inside of my mouth. I get in a taxi and go to a 24-hour western medical centre where they pump me with antibiotics.

Repaving on the square, coinciding with the anniversary

Students take me to visit Great Wall, not the bit built in 1958 for the tourists but the crumbling pile where it traverses a ridge of mountain peaks and stretches into the horizon on eitherside. We walk two hours up the mountains in the snow to find it.

The John Bull Tavern is a British Pub where the western news correspondents hang out and where I interviewed some of the veterans of 1989. Accidental Death of an Anarchist and Threepenny Opera are the biggest recent theatrical successes.

Collecting phrases and proverbs in the Beijing dialect which resembles 18th Century English in its rhetoric: insults like: "Your tongue is so long and ugly it's like a cloth that's been used for foot binding."

Finally, on my last evening, in a bar by chance I meet someone who starts telling me of their experiences in Tiananmen Square in 1989 and I listen open mouthed.

LONDON: 4 May

Been thinking uneasily about all the lies I told in China , wake in the night and remember that Wang Dan said he was keen to talk to me and assist with the play because it's important that people remember what happened in 1989.

That's why I am writing the play, and it's in fulfilment of this task that I lied. So I decide to live with this conclusion.

I never wrote a play before in less than a year. Now I've written one in seven weeks and today (four months since I set out for New York) we begin recording it with a cast of Chinese actors for broadcast on 4 June, the day of the anniversary.

Paul Godfrey's Tiananmen Square is being broadcast in the UK on BBC Radio 4 on 4 June at 2100 BST.