The play uses several devices to keep the audience in suspense. Firstly, we are aware that the Birlings incorrectly assess key events that are raised in the play; such as the Titanic sailing and the rumours of war . The reader is therefore aware early on in the play that we may not be dealing with characters of sound judgement.
The arrival of Inspector Goole is unusual and his presence (even the pun of ghoul/goole on his name) is mysterious. The way each character is interrogated and reveals an individual weakness linked to the demise of Eva Smith becomes eerily familiar by the time Mrs Birling is questioned.
Lastly, the ending of the play helps to maintain an air of suspense regarding the characters and the real impact of the inspector’s visit. The younger characters had been initially cowed by the inspector’s final speech, but the older Birlings were ready to question the reality of what had been presented to them and the validity of the inspector – not of the effect of their deeds. It is at the very end of the play, when the characters are ready to see the earlier events as a joke, that the final point is made. Mr Birling takes a telephone call announcing that an inspector is on the way to talk to the family about the suicide of a young lady. The audience is left in suspense, as the characters are, as to what has really just transpired.