The other Sunday, I watched the Beijing police beating a group of pensioners. Some retired professors were trying to protest about electricity transformers for the new Olympic Park being sited just outside their block of flats, but the authorities here cannot tolerate even geriatric dissent.
As the demonstration started, the police weighed in with sticks, hitting old men around the neck and shoulders. A woman screeched, "Stop beating him!" as they manhandled her friend. A policeman roughly shoved her into a hedge, shouting, "Shut up!" Several elderly people were briefly hospitalised; four were arrested.
The Chinese government is especially sensitive to pro tests relating to the Olympics. The 2008 Games will be China's showcase, its chance to shine on the world stage. But instead of looking after those whose lives will be disrupted by construction of the facilities, the police, in this case, chose to ignore and then tried to silence them.
With his thick grey hair, old-fashioned glasses and earnest gaze, Professor Wang Feng Gui looks like exactly what he is - a retired professor of veterinary medicine. "I have never, ever protested before," he said. "I'm almost 70 years old. I have always trusted the government unconditionally, but this incident hurt us very deeply."
It started two years ago, when the retired professors from the Chinese Science Academy heard that the city planned to erect an electricity transformer for the new Olympic Park within ten metres of their homes. A petition signed by 3,000 residents prompted officials to meet them, but although the Beijing Environmental Protection Bureau agreed that the site was too close, the project was not moved. On 19 April this year, the pensioners surrounded the area, but police pushed them back and work commenced.
A few days ago, I climbed the concrete steps to the dingy flat where Professor Wang and his friends were meeting. In 1994, Professor Hu Qingyu won the prestigious National Space Science award. Professor Gao Quan is still working on artificial intelligence and other projects likely to earn the government millions as China moves from a manufacturing to an innovation-based economy. But now they are deem ed subversives. As we talked, a crane swung alarmingly close to the window. Although some of their concerns about potential radiation may be misplaced, the short-term impact is obvious. Construction stops for only a few hours at night, the noise is unbearable, and their homes are subsiding.
"In mid-July, we noticed a big crack between two sections of that building," said Professor Wang, pointing. "Then we noticed the water coming out of the taps was murky. All four pumps had burst. Then we realised the gas pipes had burst, too. Ten families were evacuated from the building that night." The authorities fortified the building, but carried on digging the hole for the transformers. Contacted by phone, the Beijing Environmental Protection Bureau said it knew nothing about the pensioners' problem, which might be "a rumour".
The pensioners say it is an honour to have the Olympics on their doorstep, but they object to the lack of consultation. "It is against the Beijing Olym pic themes - Green Olympics, People's Olympics, High-tech Olym pics," said Professor Wang. "It's against the basic Olympic principles."
This past week, the International Olympic Committee president, Jacques Rogge, toured the steel "Birds' Nest", the extraordinary feat of architecture and engineering that will be the 91,000-seater stadium. Olympic officials are impressed with the efficiency of the Chinese, who are ahead of schedule, but they know that is not enough. "The games are not judged solely by the technical proficiency of the project, but also through the perception that the world has of the games," Rogge said.
The former Australian athlete Kevan Gos per, chairman of the Beijing Co-ordination Commission, has promised to investigate the pensioners' complaints. "In the event that there is any risk, they should be compensated," he said.
After assaulting them, the police eventually let the pensioners hold their protest. Their slogans would not have been out of place at a Middle England rally against a new bypass. "We demand a public inquiry!" they chanted. But since then, they have felt nervous. Their work-unit leaders have told them they are courting trouble. If such vulnerable people suffer because of Olympic projects, the whole endeavour may be tainted.
Lindsey Hilsum is the China correspondent for Channel 4 News