38. Based on a small sample in Putney High Street, McCahill and Norris extrapolated the number of surveillance cameras in Greater London to be around 500,000 and the total number of cameras in the UK to be around 4,200,000. According to their estimate the UK has one camera for every 14 people. Although it has been acknowledged for several years that the methodology behind this figure is flawed, it has been widely quoted. Furthermore, the figure of 500,000 for Greater London is often confused with the figure for the police and local government operated cameras in the City of London, which was about 650 in 2011. Project SCRAM is a policing effort by the Halton Regional Police Service to register and help consumers understand the complex issues of privacy and safety that confront households when dealing with installations of home security systems. "The SCRAM program enables community members to voluntarily identify and register their residential video surveillance equipment through a simple, secure, confidential, online form. " It has not been extended to commercial businesses. A wide ranging effort to provide registration and monitoring of home security and systems. "Security camera registration and monitoring is a community based crime prevention opportunity and investigative tool that enlists the help of residents and can help prevent crime on three levels. Residential video surveillance cameras can deter criminals from entering the area, can prevent crimes from occurring and help solve crimes by providing valuable evidence to the police.