Most CCTV fails to cut crime or make people feel safer, according to a research study.
Experts at the University of Leicester studied 14 systems across the country on behalf of the Home Office.
They found only one area saw a drop in the number of incidents which could be attributed to CCTV.
Professor Martin Gill, from the university, said: "Overall, areas have encountered real difficulties in using CCTV to good effect."
The study showed the only crime decrease attributable to CCTV focussed on reducing vehicle crime in car parks.
Systems covered by the research included those in town centres, city centres, hospitals and residential areas.
Professor Gill, from the university's criminology department, said: "For supporters of CCTV these findings are disappointing.
"For the most part CCTV did not produce reductions in crime and it did not make people feel safer."
Researchers said control room operation was an important factor in a CCTV system's ability to detect crime.
About half of the control rooms involved were staffed for less than 24 hours a day.
Professor Gill said: "The truth is that CCTV is a powerful tool that society is only just beginning to understand.
"It looks simple to use, but it is not. It has many components, and they can impact in different ways.
"It is more than just a technical solution; it requires human intervention to work to maximum efficiency and the problems it helps deal with are complex."