CCTV commercial manager, ADT

Says: CCTV is a proven deterrent to theft, violence and vandalism, and any retailer installing it is a step ahead in tackling these issues. If staff theft is a problem, you can rig the system to alarm whenever suspect transactions such as returns or voids occur.
Store managers can also use CCTV to view the way staff are operating and identify training needs or monitor sales activity and improve merchandising.
Systems providing colour images are preferable and the cameras need to be installed in the correct places, such as entrances and areas stocking high-risk items such as razor blades or batteries.
Digital recorders are a fraction of the price they used to be. A basic internal system typically costs about £1,000 to instal and has four small static cameras.
If you plan to use a couple of cameras, install a four-way unit. If you need four, install an eight-way unit. That way, if you need more cameras, you can install them at minimal expense.
Upkeep is minimal, aside from making sure camera lenses are clean and in focus, and that no one has moved the camera.