In the novel The Moving Finger, Mrs Cleat was the wife of an elderly gardener in Lymstock named Cleat. They lived in a house on the Mill Road. Mrs Cleat was regarded by some villagers as the "local witch" and she liked to give people such an impression, such as going about gathering herbs. When children fell sick or were injured she would sometimes remark that it was because they had offended her. Mrs Baker thought that Mrs Cleat was the one responsible for writing for the anonymous letters and told this to Jerry Burton. When he checked with Dr Owen Griffith, however, the doctor disagreed, saying that it is not so simple as that.
In the BBC 1985 adaptation of the novel, Mrs Cleat is played by Patsy Smart. She and her husband make several appearances in the show, often passing comments as onlookers of what is going on in the village. However no one explicitly states that it is Mrs Cleat who has written the letters and she is not really built up as a plausible suspect.
In the BBC 1985 adaptation of the novel, the character is played by Lucy Gleeson. The name is changed to "Robert Symmington".
Mrs Cleat is not featured in the ITV 2006 adaptation of the novel (Episode 2, Series of Agatha Christie's Marple).