The success of An Inspector Calls lies with JB Priestley’s talent with exploiting the underlying tensions within the Birling family. It is from these tensions that the drama – a thing done – flows. The characters act logically within their own moral frameworks and limited perceptions which are exposed by the Inspector who sees not the limited but the expanded impact of the families choices.
Arthur Birling is an up and coming industrialist whose progress has been smooth so far but he fears a scandal. He is not of the same class as Gerald, who treats him as an equal despite being younger, but seems to aspire to this status and have it within his grasp. Seeking to reassure Geralds mother he boast of potentially being honoured which would go somewhere to achieving this.
Clearly the class issue is a source of tension between Geralds parents and the Birlings. They are of old money whilst the Birlings are new money, men whose status relies on their wealth as opposed to some hereditary title. Arthur is well aware of this status imbalance and confides to Gerald that he is aware that Geralds mother thinks he could have done better and even stayed to his own class. The anxiety of not belonging to the hereditary nobility tells in Birlings treatment of his workers. In order to distance himself from his origins, potentially within this class or at least close to it, he treats them with suspicion, harshness and a dismissiveness verging on the contemptible. Certainly to a contemporary audience who had seen the rise of organised Labour and the creation of the Labour Party this aspiration to join the aristocracy would have looked out of step with reality. By the 1940s and 50s these were yesterdays men.
Shiela shows the greatest development throughout the play not least in her change from a self absorbed engagee. In the beginning of the play she could not take her eyes off her engagement ring when her father wanted to address her and her involvement with Eva Smith is associated with her self perception. Shiela has Eva fired from the last steady job that she has because she looks prettier than her and because she thought that Eva was laughing at her. Shielas identity is wrapped up in her feminine identity and her status as an attractive woman. A status that is always under attack by her mother who insists on treating her like a child and maybe even a doll. Her relationship with Gerald is equally complex as she suspects him of having other love interests since he did not come near her one summer. The fault lines around Sheila are significant which may go a long way to explain why she develops the most of all the characters.