Chris

The logic of television was its immediacy and its currency. In many ways it mimicked the function of the music halls that used to be in every town in the country, providing ready entertainment that was always changing as different acts came and went. Many serious actors wouldn’t go anywhere near it, even well into the modern era (Gareth Thomas famously got endless stick from his serious actor mates for taking on the eponymous role in Blake’s 7, and chucked it in after 2 seasons partly for that reason). The material resulting from television production was therefore not highly regarded as cultural artefact. Only when there was a hard monetary value to it did it begin to be properly preserved.

You can often tell which shows were made with an eye on international re-sale because they were usually shot on film and in colour, relatively early by historical standards, though this doesn’t ever have seemed to be a BBC policy and the best examples of it in UK production come from independent studios - the likes of Gerry Anderson for example. These shows have survived intact even right back into the 1960s because the film stock couldn’t be re-used.

Aside from the possibility of selling certain shows internationally there was no monetary value in programmes made for Saturday teatime television until home video recorders became widely available in the early 80s. That’s why the BBC carried on taping over stuff until the late 1970s, even after it had stopped doing so for selected examples of its output that it had begun to realise might have cultural value.