Inspector Goole is probably the most important character in An Inspector Calls. He creates big impressions and somehow reveals all about the Birling family and Gerald Croft. He interrupts their celebrations to question them over the death of Eva Smith/ Daisy Renton. In the process of doing this he makes some of the characters realise what they are really like, and how the small actions they had done in the past affected her and lead to her death.
He enters in a most appropriate way, "dressed in a darkish suit of the period”. He speaks very carefully. The inspector creates "an impression of massiveness." J B Priestley makes the inspector have a big impression to make him feel superior to the Birlings. The inspector has a habit of staring at the person before talking to them as a way of intimidating the person so that they feel he is more powerful than they are.
He acts, at first, in a way that a normal inspector would. Such as when he refuses a glass of whisky because he is "on duty”. This behaviour helps to ensure that the family believe he is a real police inspector and so they don't find out who he really is. He mostly remains calm and asks questions often. He uses the answers to manipulate them so he can question them further. When he asks his questions he jumps straight to the point; such as, "I think you know Eva Smith now don't you Mr Birling?”
He has a large dramatic impact on the characters and audience. The Inspector creates shock at the very beginning of the play. Just after he enters he drops in the point that "she'd swallowed a lot of strong disinfectant". This shocks the audience and characters as you can tell by Eric's expression "My God" immediately afterwards. This demonstrates the impact on the Birling family and hope that the audience feel the same. J.B. Priestley put this in at the beginning to make everyone feel shocked by what had happened.