Any single general television service must be restricted in the programmes which it can show at the times when most people can watch. Purely on a temporal basis, this must be so; for, except at weekends, the normal maximum viewing span of most working adults is limited to four or five hours from 6-7 o’clock to 10-11 o’clock. In that time, in a single service, there is not scope to cover much more than the staple fare of television; light entertainment shows, plays, series and serials, comedies, sport, news, current affairs, and documentaries. A single self-supporting service can be adventurous within limits, but not beyond.