CCTV is quite good at helping to mitigate public order offences. For example, here in London (with possibly the most cameras per person in the world - hard to get a reliable figure) one of the few genuinely useful examples of CCTV is to enable fast response on Friday/Saturday nights. For example, a fight breaking out outside a pub.
It is not totally unusual to see mobile CCTV units (vans with telescopic cameras on the roof) on the streets of London for this purpose. But yes, in terms of intelligence gathering or crime prevention outside of drunk and disorderly, CCTV is not very useful. A few years ago, the Met Police reckoned that in London one crime was solved for every thousand cameras[1]. Not really an endorsement to shout from the rooftops about.
It is not totally unusual to see mobile CCTV units (vans with telescopic cameras on the roof) on the streets of London for this purpose. But yes, in terms of intelligence gathering or crime prevention outside of drunk and disorderly, CCTV is not very useful. A few years ago, the Met Police reckoned that in London one crime was solved for every thousand cameras[1]. Not really an endorsement to shout from the rooftops about.
[1]:http://www.independent.co.uk/news/uk/crime/cctv-in-the-spotl...