Miss prism is a minor character who nevertheless plays a crucial role. She is governess to Cecily. She was also in
a previous employment, a maid to General and Mrs. Moncrieff. In spite of her lowly position and status, Miss Prism holds the key to the mystery about Jack's mistaken identity in the play, after twenty-nine years of anonymity. According to her account, she, as Jack's nanny much earlier, in a moment of mental distraction, mistakenly deposits the manuscript of a novel she is writing in the bassinet and places Jack, then a baby, in the handbag instead. Then, she deposits the handbag in the cloakroom in a railway station in London. Jack is later found and nurtured by the late Mr. Thomas Cardew
Before Miss Prism's confessions, on one knows that Jack is actually an adopted child except that he is a child who has come into Mr. Cardew's home through a mistake. Jack is himself unaware of his real identity and grows up not knowing that he is Algernon's brother. This leads to much of the confusion in the play.
Miss Prism is also unaware of the implications of what she has done. The suspense in the play is heightened as the recognition of the significance of her mistake dawns on her. She confesses. The mystery is thus resolved and Jack is able to claim his inheritance. All minds are put at rest. Miss prism, as it were brings light to the darkness which has engulfed the play. Miss Prism also serves to expose the absurdity of class distinction in the play. Lady Bracknell does not include Jack in her "list of eligible" suitors because he does not, supposedly, have a fortune and is of low social class. Miss Prism's confession shows how wrong lady Bracknell has been and also, how ridiculous society's attitude to social class is.
Miss Prism further expose the hypocrisy of the society. Her relationship with Dr Chasuble exposes both as hypocritical and deceitful. Finally, Miss Prism's name is symbolic. Like a prism which spits a ray of light into the different colours of the rainbow, through Miss Prism, the complex web of relationships which lie at the core of the mistaken identities in the play is unraveled.