If a CCTV camera records an incident, it has failed to prevent that incident from occurring.

@spreadys pointed out an interesting article about the role CCTV has in fighting crime. The best part of the article are the comments at the bottom.

The best one, "I'm sorry, but bragging about 500 arrests from 41,000 incidents is truly pathetic. It just shows how useless CCTV is. If the incidents took place in front of a copper, the arrest rate would have been worth crowing about. People aren't bothered about being spotted on camera."

There's another comment that links to this article. “For every 1,000 cameras in London, less than one crime is solved per year.”

"Each case helped by the use of CCTV effectively costs £20,000 to detect, Met figures showed."

"The report, written by Detective Chief Inspector Mick Neville, who runs the Metropolitan Police’s Visual Images Identifications and Detections Office, found that the public “have a high expectation of CCTV and are frequently told they are captured on camera 300 times per day”.

Public confidence was dented when the police often stated there was no CCTV working when a crime has been committed, it said.

It also said that increasingly members of the public were complaining that officers had not bothered to view available CCTV images when trying to track down criminals.

It disclosed a “significant rise in the level of complaints from the public, where it is perceived that police have not viewed CCTV. This is now approaching 100 per year.”

The report found that untrained officers were often downloading and viewing CCTV images in their hunt for evidence. The cameras were effective in crime-fighting if the images and information from them was used properly.

Detective Superintendent Michael McNally, who commissioned the report, admitted there were “some concerns” about how CCTV was being used."