A casually dressed, grey-haired Chinese man takes to the podium. "Let us begin with a look at the Gospel of Saint John." There is a rustling of pages as converts and curious open their Bibles. Almost everyone in the room is scarcely a day over 30. Most look as if they are in their early twenties. They are fashionably dressed - girls with high-heeled boots, men sporting trendy knitted hats. This is Friday night Bible class in Beijing. And it is a weekend venue of choice for growing numbers of well-off middle-class city sophisticates.

The fact that this class is technically illegal, run by pastors lacking approval from the state-sanctioned Protestant church, is not the attraction. These are not young people seeking a frisson of excitement from some underground activity. They are at the forefront of a movement sweeping China - the search for spiritual satisfaction now that Marx is démodé.

No attempt is made to conceal what is, in effect, an underground religious gathering. A sign in Chinese outside the conference room reads: "Hill of Golgotha Church meeting". A board outside the hotel lift directs visitors to Hall 5. There is not a nod towards secrecy or even discretion. There is no sense of anxiety, let alone fear, that officials could burst in to break up this illegal assembly even though police do still frequently raid house churches run by underground Protestant pastors.

A spectacular success

In fact, across China religion is undergoing a defiant and extraordinary revival. Millions of Chinese are turning to familiar traditional faiths such as Buddhism and Taoism - a mystical belief with about 400 million adherents that is China's only indigenous creed. Taoist believers, like Buddhists, visit temples across the country to burn incense, present offerings and request readings from fortune tellers. Others are finding comfort in Confucius, but it is Christianity that is leading the battle for China's 1.3 billion souls.

Many regard religion as a new force, unaware that missionaries - Protestant for the most part but also Roman Catholics - tried to spread Christianity across China in the 19th century and met with fierce opposition during the anti-Western Boxer Rebellion in the early 1900s. But it was former leader Deng Xiaoping, who effectively endorsed freedom of worship, and gave Christianity the chance to take hold, with his sweeping market reforms in 1978.

Today, two Christian faiths are allowed to operate within carefully prescribed limits: the Catholics, who must worship in churches run by the State's Chinese Patriotic Catholic Association and number about six million, and the Protestants, who operate under the aegis of their government-sanctioned religious body, the Three-Self Patriotic Movement - standing for self-governing, self-teaching and self-supporting. Their numbers are estimated at 21 million - about the population of Australia. All other Christian associations are illegal.

Those who participate in non-sanctioned churches run the risk of police raids, a beating or even jail. The situation is more fraught for the underground Catholic churches than it is for the Protestant get-togethers. An unknown number of Catholic priests, and even bishops, languish in jail, serving lengthy prison terms for their temerity in preaching allegiance to Rome. Beijing's Communist Party rulers are wary of an organisation that is so well organised and also headed by a leader - the Pope - who can command the loyalty of millions.

But that doesn't seem to put off the growing congregations. Indeed, official numbers fall far short of the actual total. Recent surveys calculate the number of Christians worshipping independently of the State churches in China to be as high as 100 million. That means that almost one in every ten Chinese may now be a Christian, making Christianity bigger than the 74 million-member Communist Party.

Bring Christianity into the conversation and everyone seems to know someone who is a convert. I heard how many of the executive staff at one smallish Beijing hotel were keen Christians. A manager at an international bank mentioned that many of his employees shared a common faith.

Visiting an elderly woman who had been taken as a child to serve as a "comfort woman" to soldiers of the invading Japanese army in the Second World War, I was astonished to see a cross hanging on the wall of the simple home she shared with her son just across the road from the local Communist Party offices. Without embarrassment or fear, her son explained how each Sunday he attends services in a house church nearby. He proudly pulled out his hymnal and sang for me, while curious neighbours peered through the window.

I learnt of the Communist Party secretary of a village not far from Qufu, the home town of Confucius, who sleeps with a crucifix above his bed. His wife, he explained, was a Christian, as were his sons. Indeed, he went on, pretty much everyone in the village of about 3,000 was a believer. Almost all, it seems, belong to illegal house churches, small congregations that come together in private homes in cities, towns and villages across China.

Why Christianity has such a hold remains something of an enigma. Many Chinese are looking to fill the chasm left by the collapse in Marxist ideology's credibility in the wake of the disastrous ultra-leftist 1966-76 Cultural Revolution and the Tiananmen Square crackdown. It's also possible that a religion from the West holds a particular attraction for Chinese looking for a more modern faith to complement the stunning success of capitalist-style economic reforms. But the sense of belonging may be the best way to explain why Christianity has been such a spectacular success story in China in the past few years.

Finding a family far from home

Pastor Ezra Jin heads the Protestant Zion Church, based above a karaoke club in one of the thousands of faceless apartment blocks that populate the suburbs of Beijing.

He prefers not to see Zion as an illegal underground Church but rather as private and independent, and in the two years since its inception, the church has never suffered a police raid. "Our Church offers people a feeling of belonging to a family," explains Pastor Jin. "There are more and more contradictions in our society as different interest groups emerge and gaps open up between regions and between social groups. Christianity can help by providing comfort and spiritual strength."

Dressed in a sharply cut dark suit with a white shirt and gold silk tie, Pastor Jin could be just another successful executive. Instead he runs a house church so large he conducts at least three services every Sunday in a room brimming with 300 to 400 people. Toddlers play in a glassed-off crèche while their parents stand to sing hymns and to pray. A choir in hot-pink robes leads the singing and a little band with an electric organ and two guitar players keeps the congregation in tune.

Liu Huan has been playing the guitar in church for nine years. The slight computer engineer in his thirties beams with delight at being asked to explain why he attends a house church. Although in this case sprawling, neon-lit office might be more appropriate. Apart from the main hall, the Zion Church seems to occupy most of the floor of the building with smaller offices and store rooms. "My wife introduced me to God and coming here gives me strength." He fits one of the models that Pastor Jin described: the out-of-town worker who has found a place in a new community far from home through Christianity.

With his spiky haircut and a single earring, Wang Ye cuts a dashing figure in the congregation. The 21-year-old is a student graduating in online business who hails from the northern coal-mining province of Shanxi. His mother, who had moved to Beijing in search of a better job and was lonely, found comfort when friends introduced her to the church. "She brought me as well. Many of us have family problems and we find warmth here." He strolls over to join a group of friends gossiping about their plans to celebrate the Chinese New Year.

"The future of Christianity in China is very different from in the West," believes Pastor Jin. "In the West, Christianity is in retreat, especially in Europe, but in China it is growing by leaps and bounds." He cites the stability the church offers to a population buffeted by decades of wrenching political change as one of most appealing aspects of the faith.

The first hymn on a wintry Sunday at his Zion Church echoes that refrain. A lay preacher leads the congregation. Projected on a screen on the wall behind him the words scroll down against a background of plum blossoms. Voices are raised in song. "There are many things I don't know in the future. But I know who will hold my hand and who will be in charge."

As readings from the Bible and prayers follow more hymns, the atmosphere in the room is charged. A verse reaches a crescendo, women in the congregation one after another raise their arms above their heads and sway. One or two sob quietly. The lay preacher leads a prayer. Each time he mentions "Our Lord", a chorus of "Amen" swells up from the crowd. Nothing is allowed to disturb their evangelical reverie and there is little sense among these worshippers that they risk arrest.

Pastor Jin believes the most difficult times for house churches such as his may soon be over. He recently took part in the first meeting between government officials and leaders of the banned underground Protestant faith.

It was the most significant step towards reconciliation in decades, and could mark a turning point in the Party's attitudes.

"I wasn't surprised," he said. "It was clear to me that sooner or later God would bring us to this." In addition, the size of the underground Protestant church has now reached such proportions that it is an increasing challenge for the authorities or the police to control. "China is a very big country so there will still be examples of persecution, but the overall direction is gradually changing."

He says the talks could be a sign that the Communist authorities have come to recognise that the Protestant church at least can be a force for harmony - the watchword of the administration of President Hu Jintao, the current head of the Party. It was President Hu himself who told an unprecedented Politburo study session on religion in late 2007 that "the knowledge of religious people must be harnessed to build a prosperous society".

"The Government is anxious to work out the way to go forward," believes Pastor Jin. "They have understood that the Protestant Church is not an opposition force but a force for stability."

A constant fugitive

But there are others who would disagree. Pastor Jin may operate in effect outside the law, but he is grudgingly tolerated. Arranging to meet him required little more than a couple of telephone calls. He chatted happily in public over a lunch of spicy Sichuan food in his local restaurant across an alley from the building housing his church.

Pastor Zhang Mingxuan falls into quite another category. Expelled from Beijing before the Olympic Games last August, he is persona non grata in the capital. He attracts police attention wherever he goes and his telephone is constantly tapped. On his first return visit to the capital since his eviction, he got off the overnight train from his home in central Henan province and met me behind a department store near the railway station.

A short, blockish man dressed in a shiny suit and with a tie embroidered with crosses, his first order of business was practical. "We've been on an overnight train and we're hungry. Let's have lunch." No sooner had he sat down, intoned grace over the food and gulped down a glass of hot Coca-Cola to counter the bitter chill on one of the coldest days of the winter than he launched into an account of his confrontations with the police. Zhang, who describes himself as a lay pastor, heads what he calls the Chinese House Church Alliance, bringing together a number of diverse congregations. Any form of organisation is anathema to the ruling Communist Party, jealous of any rival power. Beyond the pale is a grouping of illegal underground churches that could challenge its supremacy.

It is small wonder then that he recounts a convoluted tale of eviction from his Beijing flat, from the homes of friends, suburban hotels, even from guesthouses in the province that abuts the capital. Everywhere he tries to lay his head, the police track him in their dozens, moving him out of their jurisdiction. Zhang is undeterred. "My head is here. Let them take it if they want it. But God is in Heaven and he won't allow them to take my head."

A poorly educated barber and the product of an atheist Communist system, he had little time for the Christianity in which his wife believed. Or at least that was until a business deal went wrong in 1986 and a failed court case left him deeply in debt. He heard his brother-in-law recite Psalm 38: "They also that seek after my life lay snares for me: and they that seek my hurt speak mischievous things, and imagine deceits all the day long." The words cut to the heart. "I fell on my knees and in less than five minutes, I became a Christian."

He was an enthusiastic convert. He does not hide his conviction that his mission now is to spread the word of God far and wide in China. His fervour contrasts with the measured tones of Pastor Jin. Leaping to his feet, he rolls up his trousers and points to scars on one leg. "Look. I was run over and I have two metal pins in my leg. But after 15 days I could walk again because of the Lord." He spreads his arms wide and gestures to his stocky frame. "When they arrested me I fasted for 25 days. Nothing happened to me because God was with me."

He does not bother to hide his contempt for the Communist Party. Fuelled with passion, his voice rises. "They hate me but I don't hate them." God, he says, is on his side and he will win. That passion must trigger anxiety among officials who for 30 years have guaranteed freedom of worship - but not worship conducted by unofficial ministers like Zhang.

The demolition three years ago of an illegally built Protestant church near the southern city of Hangzhou draws Zhang's wrath. The building had been constructed on land intended for a commercial centre, and several hundred faithful in the town that is home to tens of thousands of Christians tried to stand in the way of the razing of the building. Secretly filmed video of the incident shows scuffles between worshippers defending their church and the police, with at least four people reportedly suffering broken bones as police wielding batons pushed back the crowd. Several were arrested and eight people were jailed for terms of up to three and a half years. For Zhang, such actions are evidence of the Communist Party's fear.

"China is a land that has been chosen by God. If the government did not interfere then many more Chinese would become followers. Our hearts are thirsty." Disturbed to learn that my Chinese colleague remains firmly atheist, Zhang leans forward across the table and tries to persuade her. "You should find faith as soon as possible so that we can all be brothers and sisters in God. God will save you. He makes so many miracles. He will protect you." A day later, he was picked up by the Beijing police and shipped back to Henan province.

An understanding with the jailers Pastor Shen Quan was trained at an officially approved seminary - as was Pastor Jin - but he too left the government-sanctioned church in search of greater spiritual freedom. It has been more than two years since police last carried out a raid on one his services, during which members of his congregation were intimidated and warned not to attend, while he was taken away and questioned. He is not as optimistic as Pastor Jin that the recent inauguration of tentative talks between government and house church luminaries heralds an end to the persecution. "This is just not possible. As long as the house churches exist, the government must want to try to control them."

But government raids on house churches have proved somewhat counterproductive. Underground Christians say that as soon as one house church is closed, its members split up and found their own small congregations, further multiplying the numbers.

One of the attractions of these churches is the personal care that a pastor gives to his flock, which is a world away from the more rigid approach of the state-sanctioned Three-Self Patriotic Church. One such - the Kuanjie Church - was full by 9am for a Saturday morning service. A far higher proportion of the congregation were middle-aged or elderly and one woman made it her duty to patrol the aisles making sure that everyone, including curious first-time visitors, fell to their knees on specially provided foam cushions during the lengthy prayers. Even in this church, the tone was evangelical. Two women with microphones on poles moved between the pews, ensuring worshippers had a chance to offer aloud their prayers and to share with the rest of the congregation their stories of individual communion with God.

But such official churches lack the personal touch found in the small house churches, and perhaps because of that are growing more slowly. The challenge now for the government is to determine how it will handle the breakneck spread of the underground churches.

Zhao Xiao is a prominent economist, a professor of the University of Science and Technology and a one-time Communist Party member. He is also a Christian and something of an optimist. He sees the recent groundbreaking talks between the two sides as inevitable. As the Christian population has grown, the Party has recognised that Protestants are making no attempt to form an alternative organisation and are not questioning the rule of the party, he says.

This may have given the leadership greater confidence to liaise with them. It is also common knowledge that huge numbers of the volunteers who raced to help with the aftermath of last year's devastating earthquake in southwest China were Christians. Many are still there, helping the survivors and, sometimes, preaching.

Familiarity, Professor Zhao believes, is another important factor. "It has taken many years to reach this point. Many meetings have taken place over the years between imprisoned pastors and their police jailers and this has bred a closer understanding. Those changes in attitude meant this day could come." He adds: "I think that one day the Communist Party will even allow Christians to become members."

END