1. The audience knows the characters' world is going to go through terrible changes
2. 1912 was just before the First World War - which began in 1914 and killed millions of people
3. Priestley wrote An Inspector Calls to challenge his audience to think about how many more disasters lay ahead for them if they didn't learn from past mistakes
Priestley presented a popular BBC radio programme, 'Postscripts', but his show was cancelled after members of the government decided Pristley's views were too left-wing (I.e. socialist)