China has more internet users than any other country in the world, according to researchers at the Beijing-based analysts BDA. The research group said China had leapfrogged the US to become the world's most powerful nation online.

At the end of 2007, figures from China's internet network information centre said the country had 210 million internet users, putting it just a few million people behind the US. According to BDA, growth rates indicated that China had now taken the top spot.

"Based on these sources, we can conclude that China has by now comfortably surpassed the United States as the world's largest internet population," said Bin Liu, an analyst with the company.

China's number of internet users is increasing by around 200,000 a day, and the dotcom business sector is expanding rapidly.

But concerns have been raised about Beijing's repressive approach - using the so-called "Great Firewall" to block sites it deems politically dangerous.

The press freedom group Reporters sans Frontières, which this week staged an international day of protest against internet censorship, said in a report that China had imprisoned a number of political dissidents, and blamed western corporations for helping.

The report said: "The hunting down of independent thinkers online is all the more effective as several major western companies have colluded with governments in pinpointing 'troublemakers'."

Last year the founder of the internet company Yahoo! apologised to the family of the journalist Shi Tao - who is serving 10 years in jail - for passing information to the Chinese government that led to his arrest and imprisonment.

Tao had received government instructions on how to report the anniversary of Tiananmen Square and his crime was to forward an email to a human rights organisation.