Mr Birling: Capitalism Personified
Mr Birling is basically everything Priestley hates about capitalism rolled into one character. He's described as "heavy looking" which isn't just about his appearance - it represents how he weighs society down with his greed and selfishness.
This guy literally treats his daughter's engagement as a business deal. Instead of celebrating love, he toasts to "lower costs and higher prices." That tells you everything about his priorities - profit over people, including his own family.
Priestley makes Mr Birling look like a complete fool through dramatic irony. When he calls the Titanic "unsinkable, absolutely unsinkable," the audience knows it's already sunk. This technique shows how wrong-headed and overconfident capitalists like Birling really are.
His name "Arthur" ironically references King Arthur, a noble and fair ruler. The contrast couldn't be starker - while King Arthur represented justice, Mr Birling represents exploitation and moral blindness.
Exam tip: Mr Birling represents the older generation's resistance to change - he's exactly the same at the end as he was at the beginning.