Clara is a character who is mentioned in the Miss Marple short story The Thumb Mark of St. Peter. Although her exact occupation is not mentioned, she is likely to be Miss Marple's maid at the time of the events in the story. Miss Marple said that when she had to go to stay with her niece Mabel Denman, she had put Clara "on board wages."
She is mentioned in The Mirror Crack'd from Side to Side. She was a St Faith's girl. Miss Marple thinks of her when she is remembering how things were in the past, when she had parlourmaids. Girls from St Faith's orphanage would come to her to be "trained", before moving on to better-paid jobs elsewhere. Miss Marple reflects on how these girls had not been very good at the telephone and not good at all at arithmetic, but knew how to wash up and make beds. They had skills, rather than education. Now, it seemed to be the educated girls who took up jobs doing domestic chores, like Cherry Baker.