[simoncarter]

In that case, the presence of the cameras gave a sense of security that was unwarranted. It didn't prevent the crime from happening, but did let the citizens think that that their presence would detract criminals, which it didn't, at least in their case, and that if there was a crime, the culprits would have a higher chance of being convicted.

[philh]

To be precise, it didn't prevent that crime from happening. You seem to be assuming that the law-abiding folks reacted to the non-working camera but the criminals didn't.

[vidarh]

As far as I remember, there is little supporting evidence that CCTV usage in the UK have much effect on crime rates.