Bankruptcies, unemployment and social unrest are spreading more widely in China than officially reported, according to independent research that paints an ominous picture for the world economy.

The research was conducted for The Sunday Times over the last two months in three provinces vital to Chinese trade - Guangdong, Zhejiang and Jiangsu. It found that the global economic crisis has scythed through exports and set off dozens of protests that are never mentioned by the state media.

While troubling for the Chinese government, this should strengthen the argument of Premier Wen Jiabao, who will say on a visit to London this week that his country faces enormous problems and cannot let its currency rise in response to American demands.

The new US Treasury secretary, Timothy Geithner, has alarmed Beijing and raised fears of a trade war by stating that China manipulates the yuan to promote exports.

However, a growing number of economists say the unrest proves that it is not the exchange rate but years of sweatshop wages and income inequality in China that have distorted global competition and stifled domestic demand. The influential Far Eastern Economic Review headlined its latest issue "The coming crack-up of the China Model".

Yasheng Huang, a professor at the Massachusetts Institute of Technology, said corruption and a deeply flawed model of economic reform had led to a collapse in personal income growth and a wealth gap that could leave China looking like a Latin American economy.

Richard Duncan, a partner at Blackhorse Asset Management in Singapore, has argued that the only way to create consumers is to raise wages to a legal minimum of $5 (£3.50) a day across Asia - a "trickle up" theory.

The instability may peak when millions of migrant workers flood back from celebrating the Chinese new year to find they no longer have jobs. That spells political trouble and there are already signs that the government's $585 billion stimulus package will not be enough to achieve its goal of 8% growth this year.

The American economist Nouriel Roubini said growth figures of 6.8% in the fourth quarter of 2008 masked the reality that China was already in recession - a view privately shared by many Chinese financial analysts who dare not say so in public.

Even security guards and teachers have staged protests as disorder sweeps through the industrial zones that were built on cheap manufacturing for multinational companies. Worker dormitory suburbs already resemble ghost towns.

In the southern province of Guangdong, three jobless men detonated a bomb in a business travellers' hotel in the commercial city of Foshan to extort money from the management.

The Communist party is so concerned to buy off trouble that in one case, confirmed by a local government official in Foshan, armed police forced a factory owner to withdraw cash from the bank to pay his workers.

"Hundreds of workers protested outside the city government so we ordered the boss to settle the back pay and sent police armed with machine-guns to take him to the bank and deliver the money to his workforce that very night," the official said.

On January 15 there were pitched battles at a textile factory in the nearby city of Dongguan between striking workers and security guards.

On January 16, about 100 auxiliary security officers, known in Chinese as Bao An, staged a street protest after they were sacked by a state-owned firm in Shenzhen, a boom town adjoining Hong Kong.

About 1,000 teachers confronted police on the streets of Yangjiang on January 5, demanding their wages from the local authorities.

In one sample week in late December, 2,000 workers at a Singapore-owned firm in Shanghai held a wage protest and thousands of farmers staged 12 days of mass demonstrations over economic problems outside the city.

All along the coast, angry workers besieged labour offices and government buildings after dozens of factories closed their doors without paying wages and their owners went back to Hong Kong, Taiwan or South Korea.

In southern China, hundreds of workers blocked a highway to protest against pay cuts imposed by managers. At several factories, there were scenes of chaos as police were called to stop creditors breaking in to seize equipment in lieu of debts.

In northern China, television journalists were punished after they prepared a story on the occupation of a textile mill by 6,000 workers. Furious local leaders in the city of Linfen said the news item would "destroy social stability" and banned it.

At textile companies in Suzhou, historic centre of the silk trade, sales managers told of a collapse in export orders. "This time last year our monthly output to Britain and other markets was 60,000 metres of cloth. This month it's 3,000 metres," said one.

She said companies dared not accept orders in pounds or euros for fear of wild currency fluctuations. Trade finance has all but ceased. Some 40% of the workforce had been laid off, she added.

Nearby, in the industrial hub of Changshu, all the talk was of Singapore-listed Ferro China, which exported steel products to customers in Britain, Germany, Korea and Japan. Last October its shares were suspended.

The company is reported to have been weighed down by $800m in debts and, according to the specialist business magazine Caijing, has started a court-or-dered restructuring.

A researcher found the gates closed and under tight guard, 2,000 employees out of work and witnesses who told of company vehicles being seized by impatient creditors. Holders of Ferro China debt include Credit Suisse and Citi-group.

Even in the city regarded as the most entrepreneurial in China, Wenzhou, the business community is reeling. "We estimate that foreign companies have defaulted on payments for 20 billion yuan (£20 billion) owed to Wenzhou firms," said Zhou Dewen, chairman of the city's association for small and medium-sized businesses.

"British businessmen are better than other customers because even if they owe money they can be contacted and promise to pay their bills if they can raise the cash but many other foreigners just disappear," he said.

Slumping demand for consumer electronics in Britain has been blamed for the crisis engulfing the southern city of Shunde, in Guangdong, where a cluster of 3,000 electrical firms has grown up around big exporters like Kelon, a white-goods manufacturer.

"The impact on us from the slowdown in the British market will be huge," said a manager at Kelon, who asked not to be named.

Shunde is one of the amazing one-industry Chinese towns that has come from nothing to generate 20% of China's export production of domestic electrical appliances, making 60% of its sales to Europe.

Now the whole province is wrestling with sudden, sharp decline. A researcher who watched officials handling complaints at a local labour bureau reported "class hatred" among workers.

"Why did the boss cut your salary? You must be lazy or absent from work," an official told one group of petitioners.

"What do you mean? Are you an official of the people's government or a slave of the bosses?" demanded an irate worker.

Their claim dismissed, the group warned onlookers: "We are thinking of taking extreme action."

A legal advocate for migrant workers, Xiao Qingshan, told a tale of violent intimidation by the state in collusion with unscrupulous businessmen.

On January 9, Xiao said, 14 security officers from the local labour bureau broke into his office, confiscated 600 legal case files, 160 law books, his computer, his photocopier, his television set and 100,000 yuan in cash.

"That evening I was ambushed near the office by five strangers who forced a black bag over my head and then threw me into a shallow polluted canal," he said. His landlord has since given him notice to quit his rented home.

Xiao said he was defying bribery and threats to speak to the foreign media because he wants international businesses to know what is really happening in "the workshop of the world".