He was nothing special, except to his parents. Not a trophy winner or football champion; not the class joker or swot. He was small for a 12-year-old, with glasses and a tentative smile - the sort of boy who blurs into the crowd in school photos, who stands aside in the corner of a playground.

"He was born prematurely, at less than eight months. He wasn't very strong, so we spent all our money seeking treatment for him," his mother told me. "We had so many hopes and expectations for him: he was the source of all our mental strength. We didn't expect him to be a 'great man' - but we hoped he would be a good one. Now we hope the government can give us a satisfactory explanation and justice."

She was speaking less than a fortnight after her son had been crushed in the total collapse of Fuxin No 2 Elementary in Mianzhu, Sichuan. He was one of 4,700 children who died when their schools crumbled around them in the earthquake that ripped through south-west China on May 12. Three months on, the government has made extraordinary strides in rebuilding a province where at least 70,000 died. Temporary homes and basic amenities have appeared with startling speed. Adults are back at business; children have returned to study. At the Olympic opening ceremony, a nine-year-old survivor, who saved several classmates, bore the Chinese flag alongside basketball player Yao Ming.

Yet behind the image of communal resilience lies an uglier story. The authorities are striving to aid millions of survivors. But they are also doing their best to silence angry families who want to know why so many schools collapsed when the buildings around them endured.

No one is speaking for these parents. Not the foreign protesters who have flagged up issues such as Tibet and religious freedom through demonstrations in Beijing. Not non-governmental organisations in Sichuan, which are painfully aware that supporting them would spell the end to their other work there. And not the handful of activists who tried, but earned themselves detention. Instead, parents are speaking for themselves, despite the harassment and threats that have dogged them over the past eight weeks. They have been dragged away from protests, prevented from travelling to Beijing to air their complaints, and warned against talking to foreign reporters.

"Now they do not even allow us to gather together," one man told me. He had agreed to speak by telephone, despite his concern that the call might be monitored. "The officials asked us to be patient. They told us we need to support the Olympics, and after the Olympics they will sort this out. But we have been waiting for such a long time ... I guess they hope that if the time is long enough we will just forget this."

When I came across Fuxin, I had been in Sichuan, covering the earthquake's aftermath, for almost two weeks; it was the sixth ruined school I had found.

By the government's estimates, 7,000 classrooms collapsed in the tremor. In Dujiangyan, children lay on the street in body bags; in Hanwang, they were stored on concrete ping-pong tables in the schoolyard; in Beichuan, the ground was thick with small corpses, ghostly with dust. The air stank of death. A teenager described lying trapped under rubble, touching the cooling skin of a classmate and knowing that she was dead. Another young boy came up to ask if anyone knew the fate of his best friend. Everywhere you went there were small bodies and welling pain and anger - magnified by the needlessness of their deaths.

In areas such as Beichuan, the force of the quake destroyed almost everything in its path. Homes and shops and offices were thrown sideways or simply crashed to the ground. Schools suffered because everything did. But in other areas, such as Dujiangyan, schools crumbled while the buildings around them stood almost unscathed. Fuxin was another of those, and the contrast between the surrounding structures and the rubble of the classrooms had roused parents' fury. Most were farmers or small traders; they were poor, largely uneducated people, who had never challenged authority.

Pain overwhelmed their fear. The parents were not just willing to confront officials; they were desperate to do so. Each day, they gathered at the site, lit candles at a makeshift shrine to their children and waited for the authorities to come and apologise. Unclaimed schoolbags lay in a grimy pile; books, pencils and a scatter of fuchsia sequins poked through the dust.

The Guardian's photographer and I arrived shortly after the town's education chief finally came to pay his respects, following repeated requests from the parents. He said the matter was under investigation, then added: "I feel sad too, but it's a natural disaster." He reminded them that 11 schools had collapsed across the city. Before us, the families' grief was metastasising into anger - a rage impossible to ignore as the parents screamed into his imperturbable face: "Why are your hearts so black?" "Why did our children die?" Fathers hacked at the remains to demonstrate concrete you could brush away like powder and thin steel frames that had buckled beyond recognition. They believed that substandard construction had claimed the lives of the 127 students who died here; and those of many more students in other schools across the province.

Across the country, millions of Chinese citizens were drawing the same conclusion. Public outrage was swelling. The state media asked awkward questions and experts came forward to condemn poor design and construction. The investigative magazine Caijing examined five schools and claimed that none of the sites had been surveyed. The government fielded questions online and promised an inquiry into whether poor building work, linked to corruption, was to blame.

When the Fuxin parents marched to higher authorities, the Communist party secretary for Mianzhu city got on his knees to beg them to stop. They ignored him. Throughout the quake zone, the authorities were showing not just humility but unusual openness. They welcomed volunteers from across the country, invited overseas relief teams and allowed reporters to cover the disaster unhindered.

For a few days in the wake of our visit it seemed as if the parents' questions might be answered. The thaw did not last long. Within weeks, the censors had ordered the media to drop the subject. Within the month, police were dragging parents away from protests. The families fought back, at first. They threatened to register their dead children for the new school year. They pledged to sue. They protested outside government offices. They spoke to activists whom they hoped might help them.

But by the time I returned to Fuxin, there was no sign of the angry demonstrations I had witnessed. The ruins of the school were guarded through the day. Plain-clothes police were watching the site, and the homes of the most vocal parents. Many of the relatives, once desperate to tell their children's stories, were now too frightened to talk. "They don't see the point of speaking to the foreign media; they don't think it's helped," one mother said. She had agreed to meet me at a nearby market and we drove around the back roads of the area, past lush, green rice fields, to avoid the attention of public security officials while we talked. Though a loyal party member, she feared retaliation if she was caught; like all those I spoke to this time, she asked not to be named.

The previous day, five of the parents had planned to catch a train to Beijing, to petition the central authorities. It is one of the few routes left to those who believe local officials are ignoring them. But an edict from on high had warned provincial governments to ensure "zero protests, zero petitioners to Beijing" in the run-up to the Olympics.

"The Public Security Bureau were waiting for our representatives when they went to buy tickets at the station. I think they must have a list of us all because they knew who they were, and told them not to go. They have told us not to make trouble," she said. "We don't want compensation; we just want someone held accountable. We don't want this to happen again," she added. As she spoke, she stroked a tiny photograph of her daughter. She was, she thought, too old to have another child; she did not sound as if she had the heart to try.

The Fuxin parents sought a full investigation. Instead, they were offered money: 60,000 yuan (£4,500), a huge sum by Chinese standards, but one that came at a cost. Parents reported coming under intense pressure to apply for the cash by signing a document that included a promise to abide by the law and maintain social order - in other words, stop protesting.

"We are not pursuing wealth; we just need justice - we want the people who deserve it to be punished," an angry father told us. "But they were extremely eager that we would sign. They forced and deceived us. The officials stayed in our rooms until 11pm or 12pm, and they told us that others all signed this and if you did not sign you would be the only person who got nothing.

"So we signed, and the next day we found that they told everybody this. We found out that we had been cheated. They got rid of the evidence, the wreckage of the school [which they levelled]. They said they had to do it to prevent infectious diseases, but it was just because it showed that the building was dangerous. My child should not have died." There was, he added, little sign of the investigation that the authorities had promised.

"I thought the government would give us justice, but it now seems that is impossible," wept another woman. "Some people still tell us that the government will solve this, but most of us think that they've been bought by officials. I haven't cried in the last three months, but I do now. Before, I thought the government would help us and if we had any trouble we could go to them. But when we went to them there was no one there."

Nor can the parents turn to outside assistance. Last month, a human rights group reported that a teacher from Sichuan had been sentenced to a year's re-education in a labour camp for "disseminating rumours and destroying social order" - that is, photographing the ruins of the schools and circulating the pictures on the internet, along with criticism of the construction standards.

Liu Shaokun is thought to be the third person held for posting such material. The family of Huang Qi, a long-standing human rights activist from Sichuan, says he was formally arrested for "illegal possession of state secrets" after helping bereaved parents and posting articles about structural failings of schools on his website. One of his articles was about Zeng Hongling, a former academic, who may have been first to be detained. According to a Hong Kong-based rights group she has been held on subversion charges after posting online essays attacking shoddy construction.

The crackdown is all the more striking because the parents have never sought to challenge Beijing's authority. It is not an issue of national sovereignty, such as Tibet; or about restraints on alternative power structures, such as religion. They were not questioning the legitimacy of the government. They were simply embarrassing it at a moment when international attention to China made officials particularly sensitive. The country's increasing space for dissent, carved out over recent years, has been squeezed by the pressure to perfect its image ahead of the Olympics. The families' voices were potent and numerous; and the problem was too complex for a single person or department to take the rap.

Corrupt officials siphoning off cash may have played a part in places. But so too, it seems, did inept designers, untrained labourers, contractors who themselves took an illicit cut of the budget, the factories who churned out poor-quality materials and the supervisors who failed to spot problems. "There was no one person clearly responsible for the incident; you would need to overhaul the whole system," says Nicholas Bequelin, a China specialist at Human Rights Watch.

The authorities' response to such complex issues was recognisable from previous scandals, he adds: pressure to take compensation in place of real redress. "The government gives signs that it's serious and transparent and more accountable - but then these efforts fade away."

"One problem," he says, "is the absence of a free press to keep the issue in the headlines. The incentive for finding out things that are going to embarrass you is just not there. A second is local inertia. Once [central government] officials have left, and the issue is not in their minds, the provincial bureaucracy reasserts itself in the old ways. It's a problem we have with a lot of positive steps the government takes."

Earlier this month, the authorities announced a £76bn recovery plan for the quake zone, promising to prioritise the reconstruction of schools and hospitals - and vowing to make them "extremely safe and solid structures the public can feel reassured about". It is not the first time school safety has been on the government's agenda. According to Caijing, last year Sichuan put aside £55m to improve dangerous buildings. An at-risk register was compiled. Fuxin was not on it.

The Chinese government faces a repair bill of almost $150bn (£76bn) from the Sichuan earthquake, equivalent to a fifth of its entire tax revenues for a single year, the state media reported yesterday.

Providing new houses for 3.9 million refugees, replacing schools and creating jobs for 1 million people are among the measures in an ambitious plan to rebuild the region devastated by the magnitude 8 quake, which struck on May 12.

Amid criticism that corruption and lax building standards may have contributed to the 69,225 death toll - particularly in collapsed schools - the authorities said a central focus of reconstruction would be high-quality public buildings.

"We will make the reconstruction of public service facilities such as schools and hospitals our priority ... and turn them into extremely safe and solid structures that the public can feel reassured about," stated a draft plan issued by the National Development and Reform Commission.

The commission - which steers China's economy - said an investment of 1 trillion yuan ($147bn) would be needed to pay for the plan. The sum surpasses the $120bn reconstruction bill for the 1995 Kobe earthquake in Japan. It is equal to the entire economic output of Sichuan last year and three times what Beijing spent rebuilding the capital in preparation for the Olympics.

The plan envisages building 169 hospitals and 4,432 primary and middle schools to replace collapsed structures in the three quake-hit provinces: Sichuan, Gansu and Shaanxi.

Another 2,600 schools that remained standing will be strengthened.

Under the plan, more than 3 million homeless rural families will get new houses and 860,000 apartments in the city will be built.

Welfare programmes will also be expanded to help the 1.4 million people driven into poverty by the disaster.

Job creation schemes will centre on an expanded 150 km-long urban corridor stretching from the provincial capital Chengdu to Mianyang. No timetable was set for the task, but the central government has previously set an eight-year goal to return people's lives to normal.

Even if the budget is allocated, that will be a momentous task. According to the state media, the direct economic loss from the disaster totalled 843bn yuan. Much of the damage is also impossible to fix with money or mortar.

Li Yan lost her child in a school collapse in Mianzhu city. She has heard that the government will pay 10,000 yuan per person in relief funds, but she says it will not even cover a third of the cost of rebuilding her home.

"We can't rebuild by ourselves without help," she said. "As well as a home, our biggest need is justice for my dead child, but I know that is something that nobody can help us with."

A teacher who posted photographs on the internet of schools which collapsed in the Sichuan earthquake has been sent to a labour camp for a year, a rights group said yesterday.

Liu Shaokun was ordered to serve a year of "re-education through labour", according to Human Rights in China. The system does not require a charge or criminal trial and is not subject to court appeals. He is believed to be the third person held after questioning why so many schools were destroyed in the earthquake.

Scores of schools across the southwestern province collapsed following the 7.9 magnitude shock. In many cases, buildings around them remained intact, prompting questions about the quality of their construction. The authorities initially responded to public outrage by promising an inquiry into whether shoddy building work was linked to corruption.

But they have subsequently silenced critics, ordering state media to avoid the subject and preventing parents from protesting. In recent weeks police have dragged grieving relatives away from demonstrations in some areas. Families have also been pressed to take compensation in exchange for signing contracts which include commitments not to protest or attempt to sue the authorities.

"Instead of investigating and pursuing accountability for shoddy and dangerous school buildings, the authorities are resorting to re-education through labour to silence and lock up concerned citizens like teacher Liu Shaokun and others," said Sharon Hom, executive director of Human Rights in China.

The group said that Liu, a teacher at Guanghan middle school in Deyang city, was detained on June 25 for "disseminating rumours and destroying social order." His wife, who has not been allowed to see him, was told last week that he had been sent to a labour camp. He had travelled through the quake zone taking pictures of the ruins of schools and circulating them on the internet, along with criticism.

The public security bureau in Deyang told the Guardian it was trying to find out more about the matter and the Guanghan city propaganda department said it had not heard of the case.

But an official with the general office of the Guanghan school where Liu worked told Reuters: "He was detained late last month by people from national security bureau for deliberately inciting families of victims to petition and disseminating anti-government rumours. They searched his home and found evidence."

The family of Huang Qi, a longstanding rights activist from Sichuan, said this month that he had been formally arrested for "illegal possession of state secrets" after helping bereaved parents and posting articles about structural failings of schools on his website.

China's human rights record and lack of political freedom are under increasing scrutiny with the Olympic games only days away. Yesterday a senior official from the International Olympic Committee admitted that colleagues had cut a deal to let Beijing block sensitive websites despite promises of unrestricted access.

Yesterday journalists at the main press centre were unable to access sensitive sites, including that of Amnesty International, which this week released a highly critical report on human rights in China.

A Chinese teacher has been sent to a labour camp over his internet photographs of schools that collapsed in the Sichuan earthquake, a rights group said today.

Liu Shaokun was ordered to serve a year of "re-education through labour", according to Human Rights in China. The system does not require a formal charge or criminal trial and there is no appeal.

He is believed to be the third person held after posting material questioning why so many schools were destroyed in the May 12 earthquake, in which around 70,000 people died.

Scores of schools across the south-western province collapsed following the 7.9 magnitude shock. In many cases, other buildings around them remained intact, prompting questions about the quality of their construction.

The authorities initially responded to a wave of public outrage by promising an inquiry into whether shoddy building work was linked to corruption.

But they have subsequently silenced critics, ordering the state media not
to report on the subject and preventing parents from protesting.

In recent weeks, police have dragged grieving relatives away from demonstrations in some areas. Families have been pressed to sign contracts granting them compensation, which include commitments not to protest or attempts to sue the authorities.

"Instead of investigating and pursuing accountability for shoddy and
dangerous school buildings, the authorities are resorting to re-education
through labour to silence and lock up concerned citizens like teacher Liu
Shaokun and others," said Sharon Hom, executive director of Human Rights in China.

The group said that Liu, a teacher at Guanghan middle School in Deyang City, was detained on June 25 for "disseminating rumours and destroying social order". His wife, who has not been allowed to see him, was told last week that he had been sent to a labour camp.

He had travelled through the quake zone taking pictures of the ruins of
schools and circulating them on the internet, along with criticism of
shoddy building work.

The public security bureau in Deyang told the Guardian it was trying to
find out more about the matter and the propaganda department of the
Guanghan City people's government said it had not heard of the case.

But an official with the general office of the Guanghan school where Liu
worked told Reuters: "He was detained late last month by people from
national security bureau for deliberately inciting families of victims to
petition and disseminating anti-government rumours. They searched his home and found evidence."

China uses the labour camps to detain suspects for up to four years. Critics say it is unfair and is used to detain political
and religious activists.

The family of Huang Qi, a long-standing human rights activist from Sichuan, said this month that he had been formally arrested for "illegal possession of state secrets" after helping bereaved parents and posting articles about structural failings of schools on his website.

His wife, Zeng Li, told reporters he had not been allowed to see a lawyer or relatives since his detention on June 10.

One of his articles was about the detention of Zeng Hongling, a former
academic detained on subversion charges after she posted online essays attacking shoddy construction, according to the Hong Kong-based Information Centre for Human Rights and Democracy.

China today said 12 officials have been sacked for dereliction of duty in response to last month's earthquake that killed more than 69,000 people.

The supervision minister, Ma Wen, said her department had received 1,178 complaints involving officials' responses to the May 12 quake and had dealt with more than 1,000 of them.

"Administrative punishments" had been handed out to 43 officials, the most serious being removal from office, Ma told a news conference on Monday.

Ma repeated promises to investigate possible corruption in the building of schools, large numbers of which collapsed in the quake. Parents have been demanding to know whether poorly built schools were vulnerable to the earthquake. Thousands of schoolchildren were among the people who died after the massive May earthquake.

She said those found to have violated laws and regulations would be punished, but gave no deadline for the completion of the investigation.

The prime minister, Wen Jiabao, yesterday said life in north-western China's Shaanxi and Gansu provinces should return to normal in two months, and reconstruction should be completed by 2010.

Wen said reconstruction in Shaanxi and Gansu should focus on repairing and rebuilding damaged housing in rural areas. More than 1.4m homes in the two provinces were flattened by the quake, affecting millions of local farmers.

The new buildings should be safe, economical, and take up less land, with safety as the top concern, Wen said, adding that schools, hospitals, and other public buildings must meet the highest safety standards.

According to official figures, 69,172 died during or after last month's earthquake, the most powerful to hit China in decades, 374,159 were injured and 17,420 are missing.

More than a million people in southern China have fled their homes because of floods that have killed 57 people, adding to the misery of last month's earthquake in Sichuan.

Seventy thousand quake survivors were among those evacuated to higher ground as storms dumped huge volumes of water into already swollen rivers. The worst affected area is the manufacturing hub of Guangdong province, where the Pearl River delta is suffering what officials said was the worst flooding in 50 years.

In the past week the average daily rainfall in the province was double the record and reached 41.5cm (16.3in) in one 24-hour period. Rivers burst their banks, killing 20 people, forcing the suspension of more than 10,000 businesses and causing economic losses estimated at 3.8bn yuan (£250m).

The worst may be yet to come. More storms are forecast in Guangdong and the neighbouring provinces of Fujian and Guanxi this week. "A major flood is feared if rain continues," Huang Boqing, the deputy director of Guangdong flood control and drought relief, was quoted as saying in the China Daily newspaper.

Across China the floods have affected more than 18 million people, damaged 902,000 hectares (2.3m acres) of farmland and destroyed 45,000 homes, according to the state-run media.

In February southern China suffered the worst ice and snow storms for decades. Last month the Sichuan earthquake killed more than 70,000 people.

Some quake survivors are having to move for the third or fourth time this year. Tens of thousands of residents of Wenchuan, the township at its epicentre, are being relocated due to fears that unstable mountain slopes may be prone to mudslides during storms over the next few days.

Chinese police blocked access to several collapsed schools yesterday as distraught parents attempted to hold mourning ceremonies for their dead children a month after the Sichuan earthquake.

The clampdown in Dujiangyuan and Juyuan came amid a tightening of media controls, as domestic journalists were instructed to focus on upbeat stories about the relief effort and foreign reporters were denied entry to the area.

"Many of the parents wanted to mourn at school today but we could not get in. There are so many police, hundreds of them, not just around the school but everywhere on the street," said one of the parents near Juyuan middle school, Liu Rongjie. "We want justice, but we also need spiritual and financial support. Hundreds of students and teachers died there. It's heartbreakingly sad."

The restrictions are a step back from the first two weeks after the May 12 earthquake, when the government was widely praised for opening the disaster area to journalists, volunteers and aid workers.

The tightening reflects political concerns that the destroyed schools could become a focus for anti-government sentiment. Thousands of children died when their classrooms were reduced to rubble even though surrounding buildings remained standing. This has prompted allegations of shoddy construction, official corruption and poor safety oversight.

Central government investigation teams have visited the sites, but will not release their findings until next Friday at the earliest.

Parents have staged demonstrations amid the debris of middle schools in Juyuan and Dujiangyuan and other areas, demanding an investigation, punishment for wrongdoing and compensation. Both towns are now out of bounds for foreign reporters, at least seven of whom have been temporarily detained in the past week by police. Others have been stopped at checkpoints or removed from the towns.

Yesterday a national official denied China was tightening up on media coverage in the disaster zone. "Our open attitude has not changed," said Wang Guoqing, vice-director of the state council's news division. "We will soon host the Olympics and even more reporters will come. Our door is open. It will not close."

The discrepancy with the situation on the ground may partly reflect some local officials' efforts at self-preservation. Although Dujiangyuan and Juyuan are closed to reporters, damaged schools in other areas, such as Beichuan and Mianzhu, are still open. A provincial government official said the restrictions were not ordered by higher authorities. "The local officials did not inform us about this, they just decided and operated on their own," said an official with the provincial foreign affairs department. "I am angry and I've reported this to my superiors."

But state propaganda officials have reportedly tried to direct domestic coverage away from the school issue. "Conditions are relatively good, but we are still not completely free to report," said a photojournalist from Guangdong province, who did not want his name published. "We are supposed to be speaking with one voice and concentrating on heartwarming stories."

News portals, which previously ran prominent stories about the structural quality of collapsed schools, are now avoiding the topic or running reports that appear to affirm the correct implementation of building standards.

The nation's main focus is on reconstruction. Temporary homes are being built for many of the 5 million displaced people and entire towns will be rebuilt. Ninety-five per cent of the buildings in Wenchuan county, near the epicentre, have been destroyed or condemned.

Chinese police blocked access to several collapsed schools today as distraught parents tried to mark the one-month anniversary of the Sichuan earthquake with ceremonies for their dead children.

The clampdown near schools in Dujiangyuan and Juyuan accompanied a tightening of media controls. Foreign reporters were denied entry to the area and domestic journalists were ordered to focus on upbeat stories about the relief effort.

"Many of the parents wanted to mourn at school today but we could not get in. There are so many police, hundreds of them, not just around the school but everywhere on the street," said Liu Rongjie, speaking near Juyuan middle school.

"We want justice, but we also need spiritual and financial support. Hundreds of students and teachers died there. It's heartbreakingly sad."

The restrictions are a step back from the first two weeks after the May 12 earthquake, when the government was widely praised for opening the disaster area to journalists, volunteers and aid workers. Now, the regime is worried the destroyed schools could become a focus for anti-government sentiment.

Thousands of children died when their classrooms were reduced to rubble. Surrounding buildings remained standing, prompting allegations of shoddy construction, official corruption and poor safety oversight.

Central government investigation teams have visited the sites but will not release their findings until June 20 at the earliest.

Parents have staged demonstrations amid the debris of middle schools in Juyuan, Dujiangyuan and other areas, demanding an investigation, punishment for wrongdoers and compensation.

Both towns are now out of bounds for foreign reporters, at least seven of whom have been temporarily held by police in the past week. Others have been stopped at checkpoints or removed from the towns.

A senior national official denied China was tightening up media coverage of the quake. "Our open attitude has not changed," said Wang Guoqing, vice-director of the state council's news division. "We will soon host the Olympics and even more reporters will come. Our door is open. It will not close."

Officially, state media is saying journalists are free to cover the disaster zone. The situation on the ground may reflect local officials trying to save their own skins.

Damaged schools in other areas - such as Beichuan and Mianzhu - are still open. A provincial government official said the restrictions were not ordered by higher authorities.

"The local officials did not inform us about this, they just decided and operated on their own," said an official with the provincial foreign affairs department. "I am angry and I've reported this to my superiors."

State propaganda officials have apparently tried to direct domestic coverage away from the schools issue. "Conditions are relatively good, but we are still not completely free to report," said a photojournalist from Guangdong province, who did not want his name published. "We are supposed to be speaking with one voice and concentrating on heartwarming stories."

Media outlets that previously ran prominent stories about the structural quality of collapsed schools are now either avoiding the topic or running reports that appear to affirm the correct implementation of building standards.

A few of the bolder outlets are still pushing the limits. The Beijing News today ran an article questioning the slow distribution of donated funds, and the latest edition of Caijing magazine has a front-page story about construction standards.

The main focus of the nation is on the huge reconstruction effort. Workers are erecting temporary homes for many of the 5m displaced people. In the long term, entire towns will have to be rebuilt from scratch. Ninety-five percent of the buildings in Wenchuan county, near the epicentre, have been destroyed or condemned.

The devastated town of Beichuan, which had a population of 30,000 before the quake, will probably be relocated dozens of miles away in Bandengqiao, state media said today.

A torrent of muddy water and debris roared down from the mountains of Sichuan yesterday after soldiers used anti-tank rockets and dynamite to drain a dangerously unstable "quake lake".

Local media said dead bodies, cars and household goods were swept downstream as the controlled flood rushed through Beichuan and other communities devastated by last month's earthquake.

Troops used explosives to blast open three channels from the Tangjiashan quake lake, the biggest of 30 bodies of water formed by earthquake-induced landslides. More than 250,000 people have been evacuated in the past two weeks amid fears that the rising volume of the lake could burst through the mud-and-rock barrier. An unknown number of the 69,142 dead and thousands of missing are below the waters.

In a move to clear drainage channels, helicopters have flown earthmovers up to the mountain site and soldiers have fired rockets at boulders blocking the flow. The measures appeared to work as the lake's water level dropped by 13 metres, Xinhua news agency said.

Officials were cautiously optimistic that a contingency plan to evacuate another 1 million people would not be needed. "The flow downstream has increased dramatically, but the dam hasn't collapsed," Zhou Hua, spokesman for the lake relief operation, said. "As things are, we don't expect to have to evacuate any more."

For many survivors, the flood is an added misery because they will not be able to salvage belongings from destroyed homes. The government said relief workers had completed 57,100 temporary homes. Refugees say the government has promised to build permanent homes for all the homeless survivors within five years.

A torrent of muddy water and debris roared down from the mountains of Sichuan today after soldiers used anti-tank rockets and dynamite to drain a dangerously unstable "quake lake".

Local media said dead bodies, cars and household goods were swept downstream as the controlled flood rushed through Beichuan and other communities devastated by last month's earthquake.

Troops used explosives to blast open three channels from the Tangjiashan quake lake, the biggest of 30 bodies of water formed by earthquake-induced landslides.

More than 250,000 people have been evacuated in the past two weeks amid fears that the rising volume of the lake might burst through the unstable mud-and-rock barrier.

In an increasingly desperate move to clear drainage channels, helicopters have flown earthmovers up to the remote mountain site and soldiers have fired rockets at boulders blocking the flow.

The measures appeared to work today as the water level of the lake dropped by 13 metres, according to Xinhua news agency.

Although the danger has not passed completely, officials were cautiously optimistic that a contingency plan to evacuate another million people would not be needed.

"The flow downstream has increased dramatically, but the dam hasn't collapsed," Zhou Hua, spokesman for the lake relief operation, told the Reuters news agency. "So far everything is happening within expectations. As things are, we don't expect to have to evacuate any more."

For many survivors at Beichuan, the flood is an added misery because they will not be able to salvage belongings from homes destroyed by the earthquake.

An unknown number of the 69,142 dead and 17,551 missing are now below the waters.

Elsewhere, however, the reconstruction effort is in full swing. According to the government, relief workers have completed 57,100 temporary homes and materials have arrived for 88,600 more. Almost a million tents have been sent to the region.

Refugees say the government has promised to build permanent homes for all the homeless survivors within five years, though it remains unclear who will pay.

Life in the quake-hit region is far from being back to normal, but businesses are starting to reopen and students will take college entrance exams in early July, one month later than usual.

According to the China Daily newspaper, 15 Sichuan provincial officials have been fired for malpractice in quake relief operations.

Last week Zhang Qiyu decided to take a break from her elite university in Beijing and volunteer at a refugee camp for survivors of the Sichuan earthquake.

Petite, pony-tailed and bespectacled, the 22-year-old swapped her urban dormitory for a tent in the Mianzhu countryside among thousands of the 5 million people made homeless by China's most devastating natural disaster in more than 30 years.

While bulldozers, mechanical diggers and cement mixers dress wounds inflicted on the landscape, she is now helping to heal the psychological scars by caring for infants at a newly-erected children's centre.

She and an army of 150,000 other volunteers - plus 130,000 soldiers and tens of thousands of construction workers - are part of a rebuilding effort that looks set to reshape not just Sichuan, but also the way the nation sees itself and relates to the outside world.

Like many of her generation, Zhang says she is now more patriotic and concerned about China. "I have grown up because so many things have happened," she says. "I used to look at events and think how they affected me. Now I consider whether they benefit my country." That nationalist ethos pervades the relief effort one month after the quake. Throughout the affected area China is doing what it has done most prolifically for the past decade: building.

The sights and sounds of reconstruction are everywhere. In Fuxin, scavengers with bolt cutters, sledge hammers and blow torches are picking through the rubble for pieces of iron and steel to take away for recycling. In Beichuan families are returning to half-damaged homes to salvage what belongings they can find for the years of migration that lie ahead of them. Concrete mixers are laying the foundations for thousands of prefab huts.

At the refugee camp in Mianyang gymnasium, the formerly cramped conditions have eased as more than half the residents are relocated. Unlike in the first week after the disaster, residents are eating meat, shaving, playing table tennis, listening to radios and, in a few more cases, smiling.

In Mianzhu's tent towns makeshift high streets have sprung up by the roadside where vendors under tarpaulin sell stock recovered from ruined shops. Some of the briskest trade is done by a man who owns a tent touting patriotic 'I Love China' Olympic T-shirts. "I've sold dozens today," says owner Feng Liping.

Zhang wears the white T-shirt, which is emblazoned with a red map of China and the slogan Zhongguo Jiayou, which literally means Add Petrol China! Formerly a football chant, the phrase has become ubiquitous since the earthquake and was most loudly heard in Tiananmen Square on the day of mourning, when a three minute-silence was followed by a burst of nationalist chanting.

In the immediate aftermath of the quake many commentators expressed hope that a new and more open China would emerge from the rubble. Prime minister Wen Jiabao won acclaim for the swift and empathetic way he responded to the needs of victims. NGOs played a key role, prompting unusual official cooperation with civil society, the leash on the media was loosened and, for the first time, the government held a period of national mourning for ordinary citizens rather than state leaders.

There is praise for the government among the vast majority of refugees in the quake zone. One month on the political fallout has been, if anything, positive for the government. Along with the turmoil in Tibet and the Olympic torch protests, the earthquake is part of a triptych of events this year that has taken nationalist sentiment to levels not seen in decades.

Zhang exemplifies a change that has made China more internally sympathetic and externally assertive. Her generation were formerly criticised as selfish "little emperors" because they grew up in one-child families during a period of rising inequality.

Lauded by parents

But now - in their patriotism and contributions to the quake relief effort - they are being lauded by parents and grandparents, who lived through materially tough and ideologically focused years.

"My parents didn't encourage me to volunteer for the Olympics because they wanted me to concentrate on my studies, but when I said I wanted to volunteer in the quake zone they just told me to take care. My dad said he would do the same if he was young."

She is based at a children's centre - a fenced-off cluster of white tents and prefabricated huts that provide space for up to 500 refugee infants to play and study. In the morning Zhang and local teachers conduct classes. In the afternoon children and their mothers are free to play with books, toys, swings and slides donated by domestic firms.

It is run by the China Social Entrepreneur Foundation, an NGO set up last year with cabinet approval that says it has raised 30m yuan for the quake relief operation. The nascent NGO sector in China is still viewed with suspicion by the communist government, but the camp manager, Wang Xiang, says the earthquake has improved the relationship. "The authorities thought of us as anarchists. That started to change in recent years, but the earthquake was a real breakthrough. The government now realises how useful NGOs can be, so they cooperate with us," he said.

The centre will soon be crammed. Volunteer workers from Jiangsu province - which has been selected as a relief partner for Mianzhu under a system that twins provinces with affected counties - are erecting thousands of temporary shelters. By the end of July the government promises that all the refugees will be able to move out of tents, and it has pledged permanent homes for all 5 million displaced people within five years.

Long before then, possibly even within the month, Wang plans to hand the centre over to the authorities. He is moving on to a bigger project - the reconstruction of an entire town in a combined operation with the authorities and other NGOs.

There is a limit to the government's tolerance of a stronger civil society. While many major international aid organisations were initially allowed into the area, controls on their movements have been tightened.

Media controls are also being tightened after a period of relative openness. But the combination of propaganda, responsive government and a series of crises has transformed the thinking of young Chinese like Zhang. At the start of the year the law student was mainly concerned with applying to study overseas. But after the Tibet unrest in March she - like millions of other young Chinese - signed up to internet sites that blamed the western media for distorting what happened in Lhasa, projecting China in a negative light, and setting the stage for the Olympic torch relay protests in London, Paris and San Francisco.

"We were angry not because of any threat to our material life but because we were not respected," she says. "We want to show we are united together."

Fang Ning, a political scientist at the Chinese Academy of Social Sciences, said the events of this year had stirred up patriotism. "The generation born after 1980 used to be considered selfish, irresponsible and westernised, but they have grown up overnight. What they did this time is really beyond expectations."

Threat to sue

Nationalism is evident even among the most disgruntled earthquake survivors: the parents of children killed in school collapses.

Amid the rubble of the Fuxin Number Two elementary school, Zhang Yunlong complains bitterly about the poor construction that he blames for the death of his 10-year-old daughter. "It makes me so angry that the teachers' dormitories just over there are still standing," he says, pointing to neighbouring structures that appear unscathed. Standing outside a shrine in the grounds, filled with photographs and toys of the 127 dead children, he says the families will sue the government if they are not satisfied by the results of an official inquiry, due to be released on June 20.

The earthquake has reminded China of its recent communist past, but the lure of capitalist economics has not gone away. In the meantime, the unifying force of nationalism is set to grow stronger ahead of the Olympics.

Zhang says she will stay at the children's camp for as long as she is needed. In the future she still plans to study overseas, but with a different mindset as a result of the events of this year.

"Now I want to go abroad not just to admire the west, but to tell them something," she says. "Before I wanted to change myself. Now I want to change the way people in other countries think about China."