Zhang Jingtong , a software engineer from Shenzhen, said he didn't feel safer when walking on streets with cameras as they weren't able to intervene in an emergency.

"I understand cameras provide clues to help police solve cases. But they don't reduce suffering, say, when you are stabbed by thieves."

In June, at least eight surveillance cameras filmed an unemployed 62-year-old man boarding a bus in Chengdu with a can of petrol, and then setting it alight.

Police identified the suicide-arsonist thanks to the footage. But the cameras did not prevent a committed assailant from killing himself and 26 other people, and injuring 76.

Even the most stringent security operation of the year - which saw Beijing locked down and under armed guard in the run-up to National Day celebrations on October 1 - could not prevent a pair of knife attacks a stone's throw from Tiananmen Square.


Qian Cong and Shen Huizhang from the Jiangsu Police Institute in Nanjing said petitioners and the disadvantaged were the main cause of crimes that would not be prevented by cameras.

"Many of the country's public policies don't consider, or even violate, the interests of disadvantaged groups. [The situation is worrying] considering that these kind of disadvantaged groups number 140 to 180 million people and many of them resort to extreme methods after year-long petitions," the two wrote in an article submitted to the forum.

But rather than listening to petitioners' complaints and attempting to solve them, the two suggested closely monitoring petitioners and analysing trends.

Privacy is also a concern. In May last year, two security guards in Shenzhen were sacked when they used cameras to watch women bathing in nearby buildings. Footage taken of naked people was broadcast on Shenzhen's police website.


But the privacy argument was rarely heard at the forum. Police chiefs did not consider it a concern, and industry experts said low public awareness meant there was little objection to the proliferation of cameras on mainland streets.