The speed with which London's ubiquitous surveillance cameras helped identify would-be bombers has prompted calls for extensive closed-circuit television networks in the US.
In the first such public effort in the US, New York is planning to begin the installation of a similar, permanent system for lower Manhattan by year's end.
In the struggle against terrorism at home, its backers say CCTV is both a forensic tool and a deterrent to all but the most dedicated suicide bombers. Sophisticated imaging technology allows cameras to alert police to unattended packages, zoom in on objects hundreds of feet away, identify license plates, and "mine" archived footage for specific data.
Opponents contend that this very technology is overly intrusive and open to abuse, raising serious constitutional questions. They also note that surveillance cameras not only are helpless against suicide bombings, but also that perpetrators may use video records to try to glorify their acts.
The British system was developed in the 1970s and '80s with little public discussion, in response to attacks by the Irish Republican Army. By the 1990s, technology improvements made it a key tool in the security cordon around central London known as the "ring of steel."
But the US has a very different constitutional system, some experts say, one that requires vigorous public debate before the government wires cities with a similar network of live, roving electronic eyes.
"We haven't even begun to have that debate over here about what that means in terms of surrendering privacy," says Ronald Marks, senior fellow at the George Washington University Homeland Security Policy Institute. "[Closed-circuit television] is a security measure that is effective in identifying people, but I don't know how effective it ... is at stopping them."
Millions of private cameras already guard building entrances, chemical plants, and malls. Most police departments in big cities, such as New York and Los Angeles, use surveillance cameras in high-crime areas and to identify traffic scofflaws. Most of those recordings have to be downloaded so the images can be analyzed.
A government surveillance center
American cities, however, don't have extensive live networks tied to a central surveillance center like London's. New York's plan is the first to emulate it.
The first 115 cameras are expected to be operating by the end of the year. By 2010, as many as 3,000 cameras could be installed. One-third would be owned by the New York Police Department and the other two-thirds by private security agencies working with businesses. All the images would feed into a surveillance center staffed by both the NYPD and private security agents.
The system will be able to identify license plates and can alert police to unattended packages or vehicles that repeatedly circle the same block. Eventually, it will be tied to a series of movable roadblocks that can be activated, with the push of a button, from the NYPD's surveillance office.
Such systems make the environment "operationally more dangerous" for terrorists, says Brian Jenkins, a terrorism expert at the RAND Corp. "They make it more difficult for attackers, short of those who are willing to commit suicide. That reduces the number of attackers and reduces the number of bombs in the operation."
He cites differences between the 2004 Madrid and 2006 Mumbai (Bombay) train bombings and the 2005 London bombings. Attackers in Madrid and Mumbai, who were not suicide bombers, placed several bombs and killed more than 200 people in each attack. London's four suicide bombers had only the bombs on their backs and killed 52.
"Fifty-two deaths is still tragic, but it's better than 200," says Mr. Jenkins.
Cameras enabled police in London to identify the 2005 bombers quickly. In the attempted attacks in London on June 29, police used the cameras to track and identify the alleged culprits and arrest them.
"That accelerated the investigation, and they were able to reassure the public that the perpetrators of this particular attack aren't still on the run," says Jenkins. "That has the effect of reducing the fear and terror that the attackers hoped to create."
But critics of such extensive surveillance say the deterrent effects are exaggerated.
"It just doesn't work," says Bruce Schneier, a security technology expert based in Minneapolis. "If you own a 7-Eleven and put a camera in your store and a robber robs the liquor store next door, that's money well spent. But if you're the town police, that's money wasted. You haven't reduced crime: You've just moved it around." As for New York's plan to emulate London's "ring of steel," he says, "At best, the terrorists would go bomb Boston instead."
Cost estimates for New York's complete system are $90 million. The first phase, which covers lower Manhattan and includes a surveillance center, will cost $25 million.
New York is "taking a page out of the London playbook, ... enamored with the idea of 'doing no small thing,'" says David Gaier, a public transportation security expert. But "the information overload will mean a lot of wasted time and effort that would be better spent elsewhere," he warns. Resources would be better spent employing more police and bomb-sniffing dogs and improving overall intelligence, say Messrs. Gaier and Schneier.
But advocates of camera surveillance argue that the cameras are a wise investment – a cost-effective equivalent of putting a police officer or London bobby on every corner or at every subway stop that needs one.
An ever-present eye
Concerns about cameras' intrusiveness – and how law-enforcement officers will use the images – remain paramount for civil libertarians and privacy advocates. Cameras today, they note, far surpass a police officer's ability to see the surroundings: They can rotate 360 degrees, zoom in on license plates hundreds of feet away, and see in the dark. They create a video record for police to archive and data-mine for decades. When used aboard helicopters and blimps, they can blanket large swaths of a city with live surveillance. All of this, they say, is open to abuse by government officials.
The New York Civil Liberties Union, in a report on the NYPD's use of video surveillance during the 2004 Republican National Convention, notes that officers aboard a helicopter who used infrared technology to videotape a nighttime demonstration spotted a couple embracing on a rooftop and filmed them. The four-minute footage eventually made it onto the Internet.
Jeffrey Rosner, one of the two in the tape, is quoted in the report as saying, "When you watch the tape, it makes you feel kind of ill. I had no idea they were filming me. Who would ever have an idea like that?"