An Inspector Calls is set in 1912 long before its first performance at the end of the Second World War. It is in fact set in a different world, one that seemed so peaceful and secure. The period from around 1901 to 1914 has largely been seen as a English Golden Age and the setting for Wind in the Willows, The Magicians Nephew and Three men in a Boat.
At the start of the play Mr Birling wants to make a “little speech”, note how he emphasises his importance with his language. He plays at being the kind little father despite the turbulent relationship with his own son Eric. In reality Birling is “not the kind of father” Eric can go to when he is in trouble but this does not stop Birling pretending. Birling makes a number of predictions. He is being set up by JB because the audience know that war does come in 1914, the coming age is one of labour/industrial strife and the Titanic sinks on its first voyage.
I think that this is of crucial importance. The Birling family are tied to the metaphor of the luxury liner with Sybl as the figure head of the ship, proud and mighty, but the one who smashes headlong into the iceberg of social responsibility.
Writing later Joseph Conrad dismissed the surprise at the loss of the Titanic by arguing that people had confused size with greatness. This is exactly what the Birlings have done. They have confused their financial and social power with greatness and their titanic is no match for social responsibility.