After the terrorist attacks of Sept. 11, 2001, local governments across the country set aside concerns over privacy and installed surveillance cameras in public streets and plazas.

Now — even after a damning report by the head of London’s extensive surveillance network and with little evidence that the systems work — police in many cities are trying to add thousands more cameras to their networks.

“‘Cameras Everywhere’ continues to be the best description of the trend in the video surveillance market,” security market analysts J.P. Freeman Co. said in a report in 2006 that estimated that a quarter of major U.S. cities were investing in the technology.

Two years later, the trend shows no sign of slowing. Officials in many cities are eager to take advantage of money from state and federal security agencies to install the cameras on street corners and intersections, and in cities that already have dozens of cameras, officials are seeking real-time access to thousands more in schools, transit facilities and private businesses:

* In Washington, Mayor Adrian Fenty consolidated monitoring of more than 4,800 video cameras in his emergency management office this spring, including more than 3,500 in public schools and more than 700 inside public housing hallways.

* In Chicago, whose network of nearly 700 neighborhood cameras is widely considered to be the most sophisticated in the nation, police in March took over monitoring more than 4,500 units in the public schools. They added hundreds of transit cameras on the city’s buses last year.

* Rochester, N.Y., police announced a program last week to install 50 more cameras across the city, paid for with state money.

* Seattle officials approved a plan this month to expand the use of cameras in the city’s parks, at a cost of $400,000.

* In Kansas City, Mo., police expanded their camera surveillance beyond the downtown entertainment district last month, adding cameras along a corridor that has been plagued in recent years by gangs, violent crime and drug deals.

* And in Austin, Texas, the police chief has called for round-the-clock camera surveillance across the city before the end of the year.

J.P. Freeman said the domestic market for such systems last year had doubled over five years, to $9.2 billion, and estimated that it would more than double again by 2010, to more than $21 billion.

‘The eye of Big Brother’?

Privacy activists have always resisted the cameras, and they find the enthusiasm to expand the programs especially troubling.

“It really does become the eye of Big Brother,” said James C. Harrington, director of the Texas Civil Rights Project.

“If you could just even keep it focused on the narrow area that the government says it’s going to, it would be a different story, but we know that every time the government opens the door, however slightly, it’s going to keep pushing until it gets that door open all the way.”

The American Civil Liberties Union has opposed public cameras in many cities, arguing in a position paper titled “Bigger Monster, Weaker Chains” that they were creating an American “surveillance society.”

“To the extent that these cameras are there to protect the public safety, it’s fine, but once they cross that threshold of getting into areas where people have a reasonable expectation of privacy, they can expect to be challenged,” said Redditt Hudson, manager of the Racial Justice Initiative for the ACLU’s Eastern Missouri affiliate.

Privacy advocates face a difficult task, however: overcoming the push for cameras by an energetic coalition of police agencies and community activists motivated to try almost anything to reduce violent crime.

“So far, I’ve been stopped by two citizens who have thanked me and said they’ve been praying for these,” said Kansas City police Sgt. Patrick Rauzi, head of the city’s camera project.

They are people like Lauri Turner, owner of the Hatbox Haberdashery in Austin, who said her shop had been the victim of crime more than a half-dozen times. “I don’t care about the perpetrator’s rights anymore, at all,” she said.

Melanie Anderson, a mother of young children in Rochester, said with relief that she could go to the store “without people asking you if you want drugs.”

“All these young guys aren’t hanging on the corner anymore,” Anderson said.

Little evidence to bolster backers

By and large, police agencies enthusiastically back public surveillance cameras, saying they deter would-be criminals and make it easier to prosecute crimes.

But there are few statistics to back them up. Nearly seven years after the Sept. 11 attacks spurred cities to deploy the networks in significant numbers, no systematic national research has been undertaken to assess their effectiveness.

“There is little if any information available to us that surveillance cameras actually reduce crime or lead to higher convictions,” Nick Licata, the only member of the Seattle City Council to vote against the city’s plan to install more cameras in its parks, wrote this month in a newsletter to his constituents.

Licata noted that he had supported the plan when it was introduced in May, but he said he changed his mind after Detective Chief Inspector Mick Neville, head of London’s Metropolitan Police, reported that the city’s network of near-ubiquitous public cameras had been “an utter fiasco.”

“Only 3 percent of crimes were solved by CCTV,” or closed-circuit television cameras, Neville said in an address to the Security Document World Conference last month. “There’s no fear of CCTV.

“Why don’t people fear it?” he asked. “The cameras are not working.”

In light of the evidence — or the lack of it — other officials are starting to have second thoughts. Fenty, for example, was forced to implement his plan by issuing emergency rules after a majority of the D.C. Council took steps to block it.

Police officials in San Francisco, meanwhile, have delayed approving installation of new cameras pending a final study from researchers at the University of California, who said in a preliminary report this spring that the city’s 68 anti-crime cameras had failed to deter street crime. Where the cameras had any impact, the interim report said, they simply moved crime down the street or around the corner.

“There are piles of studies that show the greatest deterrent to criminal and uncivil behavior in public parks is through active social programming and the presence of police or similar official personnel,” Licata said in his newsletter.

Where should crime go?

Lois Frankel, mayor of West Palm Beach, Fla. — which started using 13 cameras this year and plans to install 12 more — agrees with Licata on that point, saying video surveillance “is not a replacement for good police work.”

But that doesn’t mean they aren’t a worthwhile “tool in the toolbox,” she said.

Rochester Police Chief David Moore echoed that assessment. He welcomed plans to install about 50 more cameras in the city but said he was also beefing up street patrols, because criminals usually moved elsewhere.

Indeed, critics and some researchers make a point of the tendency of cameras to simply relocate crime.

“The real issue for us is that once you put cameras in one area, what happens is crime doesn’t stop, it just moves a little bit,” said Rebecca Burnhart, policy director for the ACLU in Texas. “That creates an incentive to put cameras on the next street and the next street and the next street.”

Austin Police Chief Art Acevedo, who has tangled with Burnhart over the city’s cameras, doesn’t understand why some would consider that a problem. If cameras chase criminals around, he said, “so be it.”

“I really believe in my heart that if you keep the heat on the criminal element, that eventually they get tired of your city, and they’ll move somewhere else,” Acevedo said.

He added: “We have lost our innocence in terms of the number of people that are getting killed and injured out here.”