Therefore, retailers will consider what they make annually against that cost to decide whether they will continue to trade in non-domestic knives. If retailers have to install new or different closed-circuit television cameras; new till prompts; new auditing systems, whether computer or paper based; new cabinets; and new security measures in store to ensure that the knives cannot be accessed by members of the public—as well as paying for the associated training—my best guess is that quite a few of them that sell only 10 or 15 such items a year will say that it is not worth while for them to continue to do so.