Just one crime is solved a year by every 1,000 CCTV cameras in Britain's largest force area, it was claimed today.
A senior Scotland Yard officer warned police must do more to head off a crisis in public confidence over the use of surveillance cameras.
Detective Chief Inspector Mick Neville said officers should up their game when it comes to making captured images count against crooks.
He said there are more than a million CCTV cameras in London and the Government has spent £500 million on the crime-fighting equipment.
But he admitted just 1,000 crimes were solved in 2008 using CCTV images as officers fail to make the most of potentially vital evidence.
Writing in an internal report, Mr Neville said people are filmed many times every day and have high expectations when they become victims of crime.
But he suggested the reality is often disappointing as in some cases officers fail to bring criminals to justice even after they are caught on camera and identified.
Mr Neville said CCTV played a role in capturing just eight out of 269 suspected robbers across London in one month.
Critics of Britain's so-called "surveillance state" will seize on Mr Neville's comments as further evidence CCTV is not working in the fight against crime.
The Government is considering whether every camera should be registered on centrally-held CCTV maps.
Earlier this year a Home Office report found camera schemes have a "modest impact" on reducing crime.
Researchers found cameras were most effective in preventing vehicle thefts and vandalism in car parks.
Some local authorities have been forced to make freedom of information requests to police forces to try and work out if CCTV cameras are effective.
The Metropolitan Police is piloting a scheme, known as operation javelin, to improve the use of images from existing cameras.
Staff in 11 boroughs have formed dedicated Visual Images Identification and Detection Offices (VIIDO).
They collect and label images before passing them to a central circulation unit that distributes them to officers, forces and the media.
Some 5,260 images have been viewed so far this year with identification made in more than 1,000 cases.
Mr Neville said the scheme should be expanded to force-wide as officers make the investigation of CCTV evidence as professional as fingerprints and DNA.
Former shadow Home Secretary David Davis said it is "entirely unsurprising" that the report highlights some shortcomings of CCTV.
He said: "It should provoke a major and long overdue rethink on where the Home Office crime prevention budget is being spent.
"CCTV leads to massive expense and minimum effectiveness. It creates a huge intrusion on privacy, yet provides little or no improvement in security.
"The Metropolitan Police has been extraordinarily slow to act to deal with the ineffectiveness of CCTV, something true both in London and across the country."
Detective Superintendent Michael McNally, who commissioned the report, said improvements in the use of CCTV can be made.
He told Sky News: "There are some concerns, and that's why we have a number of projects that are on-going at the moment.
"CCTV, we recognise, is a really important part of investigation and prevention of crime, so how we retrieve that from the individual CCTV pods is really quite important."
A Metropolitan Police spokesman said: "The Metropolitan Police is currently the only police service to employ this method of CCTV tracking."Reuse content