Closed circuit television (CCTV) is one of the few industries that has proved almost completely recession-proof. Aggregate turnover of the main UK installers and suppliers of CCTV systems is expected to top pounds 100m in the current financial year - nearly a 400 per cent increase since 1986.
The silicon chip revolutionised CCTV, dramatically reducing the bulk and increasing the remote-controlled manoeuvrability of cameras. Scotland Yard's traffic control centre, for example, uses 120 cameras perched on buildings and poles across London to monitor traffic black spots.
Each camera can be rotated full circle and swung up and down.
But did technology fail in Bootle? Nobody watching the film intervened to stop James being taken away. And the pictures had a fuzzy, frosted-glass quality: it took several days for enhancement to make any attempt at identification of the abductors possible.
The industry explains that the video surveillance systems installed in shopping centres are not designed to record identifiable facial features. Developments in video and recording technology over the past decade have produced equipment capable almost of counting the hairs on your head. Police operations against football hooligans, for example, have been boosted by the latest image-recognition apparatus, which can pick faces out of a crowd. But these capabilities are not thought necessary for large public spaces.
'Shopping centre managements need to know what is generally going on for security and safety,' said Paul Fletcher, technical director of Photo- Scan, which supplies Harrods and the Royal Mint.
The cameras are focused at long range to cover the widest possible area. The managements are interested in monitoring crowd build-up, fights and the formation of groups of troublemakers.
If they want to look for individual faces, they have to 'pull up' small sections of the frozen frame. As with still photography, said Mr Fletcher, the more the image is blown up, the grainier it becomes. ADT Security Systems, which installed the New Strand equipment, refused to comment on the pictures, pleading client confidentiality. But, Mr Fletcher said, 'they looked as if they came from a camera mounted high looking towards a doorway with a lot of light behind. People would have been seen in silhouette, making it more difficult to make out features.'
The Home Office and police forces have expressed concern at the quality of some of the surveillance equipment on the market, particularly following successful challenges in court of video evidence. Robert Haymon-Collins, marketing manager of the British Security Industry Association, said buyers of the equipment 'are starting to want more information about the people they are looking at'.
Mr Fletcher said that the standard video recording tape is three hours long. In many systems, this period is stretched, sometimes up to 480 hours, by regular snapshots up to several minutes apart. By this method, one tape can record several screens, taking snapshots of them in sequence.
Tapes are not looped, but often recorders are programmed to wind back to the beginning and start again every three hours. Regular maintenance is vital for good results. It is often advised that tapes be replaced after 25 operations.
Many CCTV systems are designed to avoid the need for people to sit in front of them 24 hours a day. Incidents have often been overlooked by people suffering from 'screen fatigue'. The more sophisticated systems now include movement detectors which set off alarms at intrusions into the spaces under surveillance. This alerts the human monitor to check the relevant screen.
Mr Haymon-Collins said that CCTV will always need human monitors to take decisions. The IRA's bombing of the Carlton Club in 1990 was a classic example, he said.
Initially, the police hoped that entrance hall surveillance cameras had gathered vital evidence. Later it emerged that somebody had forgotten to switch on the video recorder.Reuse content