In the novel N or M?, Patrick Maguire was the husband of Mrs Perenna, and the father of Sheila Perenna.
According to Sheila, Patrick had been a follower of Casement in the last war, and had been shot as a traitor. She said that he had "worked himself up" with other Irishmen, and was a martyr to some people and a traitor to others. However, Sheila thought that he had just been stupid.