Relations between academic historians and producers of television documentaries have always been uneasy. Historians are maybe offended by the superficiality and incompleteness of programmes made without their active collaboration; while producers resent efforts by academics to impose their standards and concerns in a field which may, they think, lie outside their area of competence. What lies behind this mutual unease is, I think, a serious failure in communication between the two professions. Each misapprehends the job of the other; makes wrong assumptions about what the other can or should do; and as a result is unable to appreciate fully either the other's achievements or his limitations. In the previous chapter Donald Watt examines this problem from the standpoint of the professional historian: I write as a producer of historical documentaries for mass audiences.

Let me say right at the beginning that what seems to me to be at the heart of the matter is the question of the commentary which is an integral part of every documentary: who should write it, how should it relate to the film, to whom should it be addressed, and above all, what should it contain?

Most television documentaries are fifty minutes long. So let us consider just how much can be said in fifty minutes. B.B.C. newsreaders, who are professionally trained to speak rapidly and comprehensibly, talk at about 160 words a minute; which means that by talking non-stop they could deliver, in fifty minutes, a text not twice as long as this chapter. But in fact, as a rule of thumb, competent documentary producers begin to worry when a commentary takes up more than about a quarter of a programme's length.