Just seen this on The Independent website - interesting that Dover is being quoted nationwide!
"Dover council introduced CCTV in 1993. After 12 years, they found that burglary in the areas covered had halved, car crime was down 87 per cent, but public disorder and crimes of violence had almost trebled.
A study in Gillingham, also in Kent, concluded that crime in the High Street had fallen by a third five years after CCTV was installed, while it was static in areas where there was no CCTV."
http://www.independent.co.uk/news/uk/crime/the-big-question-are-cctv-cameras-a-waste-of-money-in-the-fight-against-crime-822079.html