Bruce Schneier? https://www.schneier.com/blog/archives/2008/06/cctv_cameras....
The BBC? http://news.bbc.co.uk/2/hi/uk_news/england/london/8219022.st...
A meta-study on the effectiveness of CCTVs in the UK? http://ipvideomarket.info/report/is_public_cctv_effective