A classification code, recorded repeatedly along with program material, is recovered on playing a video recording, and used to inhibit replay if the recovered code matches any of a set of codes specified by the user. The codes which cause replay to be inhibited can be set by the user after entering a personal identity number. The user can optionally request that a code be recorded when recording a program. Signals are optionally provided so that an auxiliary device, such as a second video player, can be controlled in response to codes recovered. One application is to prevent children viewing certain video recordings without parental permission.