In the UK the government decided to place a large number of closed circuit television cameras in public places to deter crime and terrorism, particularly IRA bombings.
The so called ring of steel was widened in 2003 as a response to rising crime rates.
Now some are calling the effectiveness of the camera system into question:
Massive investment in CCTV cameras to prevent crime in the UK has failed to have a significant impact, despite billions of pounds spent on the new technology, a senior police officer piloting a new database has warned. Only 3% of street robberies in London were solved using CCTV images, despite the fact that Britain has more security cameras than any other country in Europe.
The warning comes from the head of the Visual Images, Identifications and Detections Office (Viido) at New Scotland Yard
One has to wonder if that 3% was worth the investment, or if the funds could have been better spent to achieve the same, or better, effect on the rate of street robberies.
For a completely different take on the ring of steel, Charles Stross's work The Concrete Jungle is a very good read if you're into Lovecraftian horror.