IMAGINE IT. York police have been tipped off there's an area of waste ground being used by a drug dealer.

They don't know when he's going to be there: so a stake-out's not an option. But what if they could quickly put up a sophisticated digital surveillance camera to observe the area - one rigged to alert operators whenever there's suspicious activity late in the evening?

Sounds like science fiction - or maybe an episode of the BBC's MI5 drama Spooks?

Maybe not. If council chiefs in York bite the bullet tomorrow and approve spending £200,000 to upgrade the city's CCTV system, it could easily become a reality.

Over the last decade, CCTV has become an important crimefighting tool. Cameras mounted in shops, banks and other businesses can provide vital evidence that helps police trace shoplifters and even robbers.

The network of 60 council-operated cameras that monitor York's streets and car parks, meanwhile, have also helped police tackle on-street crime and antisocial behaviour.

Trained council operatives sit in the control room at Police HQ in Fulford Road, from where they can quickly alert police if a brawl breaks out, say in Micklegate late on a Saturday night.

In the days before CCTV, it was all too easy for those who had been involved in a punch-up to deny everything once the police arrived on the scene, says Inspector Colin Moreton, of York police.

"If you saw a group of people involved in something, it may be that by the time police officers got there, they were all saying 'it wasn't me'," he says. "CCTV has really been very useful. It means someone can have been watching the incident since it started. They can talk to the police when they get there, and help them target the right person."

Effective as it is, however, York's network of 60 council-operated "eye-in-the-sky" cameras is far from perfect - even though the council insists it is now in full working order after an Evening Press investigation a year ago revealed more than a quarter of the cameras were not functioning properly.

Firstly, whatever the quality of the cameras themselves, recording is done using videotape. That means the recorded images are often frustratingly fuzzy.

The system is also inflexible. The 60 cameras are more or less fixed - so that police and the council cannot, for example, respond to a localised crime surge by stationing cameras to "watch" a particular group of shops or homes that has been targeted in a series of break-ins.

To add to the problems, the central "exchange" that links all the cameras is at full capacity - so there is no room to expand the city's network.

It is time, believes Peter Evely, the city council's head of network management, to move into the digital age. The problem with the existing system, he says, is that every one of the CCTV cameras observing the city's streets is connected by its own fibre-optic wire to the central "exchange", based in St Leonard's Place.

That is both hugely expensive - the council has to pay for the wires, some of which are very long - and it makes moving cameras very difficult.

The "exchange" itself is like something out of Noah's Ark, he adds. "It's like one of those old-fashioned telephone exchanges where there are wires coming in and an operator has to take one wire out and plug another one in to give someone else access."

The plan is to spend £85,000 replacing that 18-year-old exchange with a state-of-the-art digital one, that would be able to handle 120 cameras.

A further £90,000 would be spent on a radio network "mesh" that would link all the cameras using a special radio frequency, without the need for messy wires.

The final piece of the jigsaw would be a move to digital, as opposed to video, recording - a move that would cost £35,000, but would make for much better quality recordings, and much easier retrieval of CCTV footage, Mr Evely says.

The benefits would be considerable, he believes.

The upgrade, if approved tomorrow, would mean:

The number of cameras covering the city centre could potentially be doubled, from 60 to 120. There are no specific plans to buy new cameras straight away, Mr Evely says. "But people in the community who had a specific interest could perhaps sponsor a camera."

Cameras could be moved at will, and at any one time put where the police or council thought they might be most useful. "All you'd need is a plug, and somewhere to hang it (a camera) on the wall," Mr Evely says. That would mean, for example, that if there was a big event, such as York races, extra cameras could be laid on to watch the crowds, or to keep an eye on potential trouble spots. These could be monitored live from the CCTV control room, so that police officers could be dispatched quickly when needed. Cameras could also be moved as and when needed to cover crime hot-spots in the city.

Digital recording could mean much better quality pictures being available for use as evidence in court - potentially a massive help to police, Insp Moreton admits. "Definitely, an improved quality of image would help get convictions in court," he says. Digital recording would also do away with the need for police to sift through hours and hours of cumbersome video footage to try to find the tape which might have recorded a particular incident, Mr Evely says. "You would just need to type into a computer, for example, 4.30pm on Tuesday November 29, Nunnery Lane car park, and it would bring the recording up." It was digital recordings like this that helped police get on the track of the second London bombers so quickly, he says.

Cameras could be used to zoom in on a particular incident and quickly blow it up without too much loss of image quality - just the way they do in Spooks. Cameras could also be set to observe a particular area where police thought there might be something going on, and to alert an operator the moment anything happened there - known in the business as "masking". "That's ideal for crime prevention," Mr Evely says. "If there was an area where you suspected a drug dealer was operating, for instance, you could keep an eye on that - even on a particular bench you thought he might be using."

Theoretically, it might be possible for some cameras located in city shops to be linked to the council system, though there are no immediate plans for this.

The system could also mean live, high-quality images of York city centre could be posted on the web, Mr Evely says - great for promoting tourism, perhaps.

Under the Traffic Management Act, local councils like York might soon have new powers to issue fixed-penalty fines to motorists who commit minor traffic offences such stopping on a yellow box at a junction, driving the wrong way down a one-way street, or driving in a pedestrian-only zone. It would be quite possible, Mr Evely says, for the council to mount a camera in a car, and then use this mobile camera to target any street the council wanted, any time, to catch motorists red-handed. That is not, he says, something that is immediately on the cards, however - not least because the council has not yet been given its new powers under the Act.

Overall, Mr Evely says, the upgrade would make possible a much more flexible and effective network of security cameras. "It would mean we could do so much more," he says.

Criminals and irresponsible motorists take note.

Updated: 10:12 Tuesday, January 31, 2006