Doctor Who is childish, but most often in the best sense of the word. It was designed to fill the Saturday evening slot between the sports programmes and later variety and quiz shows, something that had a whole family appeal, and I think it has mostly kept that ethos over its 50 years.

Accessible "starter" episodes include "Rose", "Smith and Jones", or "The Eleventh Hour". Many new viewers have been converted by seeing the atypical but excellent episode "Blink".