According to an article posted on Boxun.com, a US-based Chinese-language site, Li Zhi, a Yahoo! customer, was given a prison sentence in December 2003 for speaking out against Beijing. It claims the state’s case was built on electronic records provided by the company.

The report has angered freedom of speech groups, which claim that Western companies are systematically co-operating with the Chinese authorities in ways that would be unacceptable in their home markets.

In September, Yahoo! was accused of aiding Beijing in identifying Shi Tao, another cyber-dissident, who was sentenced in April to 10 years in prison for making state information public. The company defended itself in that case by saying it had to obey local rules.

Commenting on the Boxum.com report, Reporters Without Borders, the press freedom group, said: "We were sure the case of Shi Tao, who was jailed … on the basis of Yahoo-supplied data, was not the only one. Now we know Yahoo works regularly and efficiently with the Chinese police."

Yahoo! was not immediately available to comment when Times Online tried to reach the company this morning.

Overnight, the company told Reuters it was looking into the matter. "As in most jurisdictions, governments are not required to inform service providers why they are seeking certain information and typically do not do so," it said

"We would not know whether a demand for information focused on murder, kidnapping or another crime."

But the latest allegations will place further pressure on American companies that already face fierce criticism for entering the Chinese market on Beijing’s terms.

The San Francisco Chronicle reported over the weekend how the head of Google’s operations in China, Kai-Fu Lee, was met by chants of "Shame on Google" and "Google, don't be evil" when he went to speak at Stanford University, the alma mater of Google’s billionaire founders, Larry Page and Sergey Brin, this week.

The protests followed the company’s decision to launch Google.cn last month, a service that censors websites forbidden in China.

In December, Microsoft, the third large player in the internet market, courted controversy when it emerged it had shut down a Chinese blog on its MSN Spaces site.

It was alleged that the move to shut down the blogger, who wrote under the pseudonym Michael Anti, came even though there was no official government protest.

Following the Boxum.com report, Reporters Without Borders has called on Yahoo! to supply a list of any other cyber-dissidents it has provided data on.

Boxun.com published an article by Liu Xiaobo, the veteran Chinese activist. The article cited a plea from Mr Li’s lawyer, Zhang Sizhi, at an appeal court hearing in February 2004.

Mr Zhang said his client, who used the e-mail address libertywg@yahoo.com.cn and Yahoo! user-name lizhi34100, had been sentenced on the basis of data handed over by Yahoo! Hong Kong in a report dated August 1, 2003.

To have your say on Yahoo! and China's restrictions on the internet, click here.

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