 The episode titles "1964", "1966", "1967", "1970", "1974", "1979",  "1984", "1987" and "1995" were the years in which the action took  place. Many of these (1964, 1966, 1970, 1974, 1979 and 1987) were  years in which General Elections took place in the UK, against which  the events of the episodes were set.