More than 200,000 incidents have been picked up by CCTV cameras over the past four years, at a cost of 42 million.
But experts admit that it is still not known how many crimes they have solved.
Figures on the number of convictions secured using CCTV evidence are not recorded, but information released to The Scotsman under the Freedom of Information Act suggests significant differences in the effectiveness of cameras across Scotland, with some areas showing much higher arrest rates than others. The findings follow recent comments by the man in charge of London's CCTV network, who branded the cameras "an utter fiasco" for failing to cut crime.
Police also say that while CCTV is a valuable tool for investigating crime, footage rarely secures a conviction on its own.
In an attempt to make CCTV more effective at deterring crime, officials in Glasgow are considering using lights and speakers on cameras that can be activated when the network operator believes a crime is about to occur.
According to the figures – released by local authorities and police – just 14 per cent of the incidents caught on camera last year led to an immediate police response and an arrest.
Opposition politicians are now questioning why so much has been spent on CCTV without any clear way of evaluating the system's effectiveness. A government report assessing the impact of CCTV will be published later this year.
Responding to The Scotsman's investigation, Patrick Harvie, the Green MSP, said: "Successive governments have, without public consultation or consent, brought in a radical surveillance society.
"There are now more cameras per person in Britain than anywhere else on the planet, despite the Home Office's own research showing that CCTV cannot be deemed a success.
"The money would be better spent on community policing, crime prevention and better resources for victim support."
A massive amount of public money has been invested in CCTV. The 1,566 cameras operated by the 25 councils and police forces that provided data to The Scotsman cost 27 million to purchase, with running costs of nearly 15 million accrued over the past four years.
Bill Aitken, the justice spokesman for the Scottish Conservatives, said: "CCTV is all well and good, but it simply doesn't work if there is nobody to answer the call. We need extra police officers on the street to deal with these incidents being spotted.
"What might also be necessary is to look again at the number of cameras and their locations to make sure they are being effectively deployed."
His concerns have been echoed by Jago Russell, the policy officer for the civil liberties pressure group Liberty:
"Surely we would be better spending these millions of pounds on proven crime deterrents like more police on the streets?"
Walter Kean, the man in charge of CCTV in Glasgow, admitted here were doubts about its effectiveness. However, he said the cameras provided police and councils with a valuable weapon in the fight against crime and anti-social behaviour. Between April 2007 and March this year, 14,264 incidents were caught on CCTV in Glasgow. More than 1,500 on-the-scene arrests were made thanks to the cameras.
Mr Kean, the general manager of Glasgow Community and Safety Services, which operates the city's 400 publicly-funded CCTV cameras, said an unknown number of arrests would also have been made by police after reviewing CCTV footage.
He insisted that the benefits of CCTV extended to identifying missing children and aiding the work of council services by spotting local problems, such as burst water mains and abandoned cars.
But he conceded that it was unclear how successful CCTV was at solving and deterring crime. "It's very difficult to look at statistics and say whether CCTV is working or not. There are too many reports saying 'maybe it does, maybe it doesn't'. But we are convinced it is beneficial," he said.
"How many people get convicted on the back of CCTV? I would struggle to tell you. And how many have been charged on the back of CCTV? I wouldn't know either." He added: "CCTV doesn't make a difference on its own. If we had more resources, we would make better use of CCTV footage.
"But that's not to say CCTV isn't working. It is. It is helping to direct resources in Glasgow to where they are needed. CCTV is feeding heavily into the city- centre policing plan. A police officer sits in our centre on a Friday night and directs officers on the basis of what they see."
He continued: "More people are arrested because of CCTV. There is less fighting because of CCTV. If it hadn't been for CCTV, none of the 21/7 bombers would have been caught."
He also rejected suggestions from human rights activists that the spread of CCTV has become a threat to civil liberties: "If you're in the city centre doing no wrong, you will never feel any impact from CCTV. If you're in the city centre and start to cause trouble, you would expect there to be some consequence."
But he accepts the increased use of CCTV may have its downsides. One might be that they are discouraging the public from reporting crime: "I think there's a real risk that CCTV will do the community's duty. Sometimes that's a problem."
Mr Kean said CCTV only reduced the fear of crime when the public saw an immediate police response to incidents: "There's a need to feed that back to communities to say 'because of CCTV, this is happening'. The time between CCTV capturing an incident and someone being convicted can be very long."
Mr Kean's comments follow concerns raised by Detective Chief Inspector Mick Neville, of the Metropolitan Police, who described the use CCTV to convict criminals as a "fiasco".
He said: "Billions of pounds has been spent on kit, but no thought has gone into how the police are going to use the images and how they will be used in court. It's been an utter fiasco."
One Lothian and Borders police sergeant told The Scotsman that CCTV was "highly useful" in catching suspects. But he added: "Image quality can be a problem. When it comes to bringing a case to court, prosecutors, as a general rule, prefer eye witnesses."
A Crown Office spokesman said: "CCTV footage of a criminal incident can be instrumental in the decision by an accused person to submit an early guilty plea. Where there is a trial, CCTV footage is often used by the Crown in evidence in court."
Plan to deter crime – not just record it
WORK is now under way to make CCTV cameras stand out in a bid to deter more crimes.
Scotland's Violence Reduction Unit (VRU) is testing a camera in the centre of Glasgow which is fitted with a powerful light that can be activated when the operator believes a crime is about to be committed.
Karyn McCluskey, deputy head of the VRU, which is based in Glasgow, said: "CCTV was brought in to record crime and identify offenders, but we think it can do more to prevent crime.
"It's cold comfort if you've been assaulted and it has been caught on CCTV, but the camera didn't prevent it in the first place."
The move is seen as vital to unlock the potential of CCTV as a crime deterrent.
Walter Kean, general manager of Glasgow Community and Safety Services, an arms-length joint council and police body in charge of the city's CCTV network, said the cameras' ability to deter crime had been slowly eroded over time.
"In terms of public-space CCTV, it's become acceptable within the public domain," he said. "When you went from the train station to here, how many cameras did you see?
"The cameras aren't hidden, but they just blend in," he said. "If people were totally aware they were being recorded then, in reality, they wouldn't do it. But nine times out of ten they are under the influence of drink or drugs, so whatever happens, happens."
It is understood officials are also considering using speakers so people can be warned about their behaviour when the cameras spot something suspicious.
Such a CCTV system – using enhanced cameras with speaker systems to allow workers in control rooms to speak directly to people on the street – was trialled in Middlesbrough last year.
The Home Office said it led to an immediate drop in anti-social behaviour, and rolled the system out to 20 other communities south of the Border.
1,566 – number of publicly-funded CCTV cameras in 25 local authorities and police forces which provided figures.
27.2million – the purchase cost of Scotland's CCTV cameras.
14.8million – the running costs of CCTV since 2004.
205,239 – the number of incidents recorded on CCTV since 2004.
43 – the average number of incidents recorded in Glasgow every day.
44,000 – number of incidents filmed last year in ten council and police force areas
6,200 – number of arrests last year as a result of CCTV in those same areas
15,011 – number of incidents filmed in Edinburgh last year
1,881 – people arrested as a result of CCTV in Edinburgh
59 per cent – proportion of filmed incidents resulting in arrest in Fife
8 per cent – proportion of filmed incidents resulting in arrest in Midlothian
350 – number of full-time police officers which could be bought for the public money spent on CCTV in the past four years.
1,400 – the number of prisoners who could be locked up for the same amount of cash