In the novel The Clocks, Mrs McNaughton is the wife of [[Angus McNaughton, a retired Cambridge mathematics professor, and occupant of 63 Wilbraham Crescent. As part of their property adjoins that of No. 19, he was questioned by the police as a potential witness when a dead body was found there.
Mrs McNaughton greeted Inspector Hardcastle with a worried expression on her face but the inspector noted that she always appeared to have a worried expression on her face. She seemed relieved that the interview was about the murder and not, for example, about their TV licence. Mrs McNaughton proved an unreliable witness. She claimed to recognise the dead man when Hardcastle showed her a photo but Hardcastle was sceptical. He recognised from his experience that Mrs McNaughton was someone simply "anxious for the excitement of having seen someone connected with murder. The longer she looked at the picture, the more sure she would be that she could remember someone just like it." At the conclusion of the case, Hardcastle wrote to Poirot. Mrs McNaughton had now claimed to have seen.... but Hardcastle commented: "Did she really?"
Towards the end of the story, counter-espionage agent Colin Lamb visits the McNaughtons again and this time he helped her with her shopping bag. He noted three bottles of whisky concealed under a packet of sheet gelatine and surmised why she sometimes seemed garrulous, sometimes appeared unsteady on her feet, and possibly why her husband had retired so suddenly from his professorship at Cambridge.