Mrs O'Grady was created by Annette Billingsley as a character in her thirty-two book series of The Troubleseekers children's novels. She was an old woman who lived in a cottage away from the Troubleseekers. She did not believe in ghosts, and she felt that mysteries were terrible things.
In a world created by fictional books Martha Jones had read, Mrs O'Grady was temporarily brought to life by a Ch'otterai. When the Tenth Doctor asked if she had a first name, she replied, "Yes I do: Mrs." (PROSE: The Mystery of the Haunted Cottage)