Chinese authorities have been forced into a last-minute climbdown over a plan to force manufacturers to bundle internet filtering software into every new personal computer sold in the country.

PC-makers would have been required to install the Green Dam Youth Escort filter in every machine produced for sale in China from tomorrow.

But with just hours to go before the introduction of the hastily-announced rules, the Ministry of Industry and Information Technology bowed to public anger over censorship and criticism from the US and industry groups, who condemned the move as politically intrusive, technically flawed and commercially unfair.

The filter was primarily aimed at stamping out pornography and shielding children but the official Xinhua news agency said that its introduction would now be delayed. The announcement gave no date for a fresh launch, a signal that it could be postponed indefinitely after the storm of outrage online.

Green Dam blocks some pornography, but also scoops up politically sensitive terms. For example, it blocks the cartoon cat Garfield due to filters set to block “white” images” as well as “yellow” – the Chinese term for pornography.

It also bars the film star Johnny Depp and socialite Paris Hilton but is far less strict when it comes to allowing images of naked black girls to slip through. Apparently the word "black" is not on the lengthy list of banned terms.

Most worryingly, Green Dam leaves computers vulnerable to outside attack, although its manufacturer had pledged to plug those weaknesses.

In what appeared to be a face-saving device, the announcement said: “The Ministry would also keep on soliciting opinions to perfect the pre-installation plan.”

The public had been particularly enraged at the secrecy surrounding its rollout and the lack of transparency or any sign of a bidding process in the choice of the software company selected for the lucrative contract.

Wang Junxiu, an internet entrepreneur in Beijing who has objected to Green Dam and other forms of censorship, said the plan appeared to be poorly thought out and doomed to failure.

"The leaders apparently decided the controversy and problems were too much and decided to make a break. If this had been a well-prepared plan with senior support, the result would have been very different. But it wasn't," he said.

The Green Dam initiative coincides with a tightening of government controls on Internet use, possibly as China prepares to present a squeaky clean image to the world as it prepares to celebrate the 60th anniversary of the founding of Communist China on October 1.

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