Doctor in the House S04E25 - The Rumour

Mrs. Loftus returns to work as a nurse at the same time that Annabel, Lady Cornford's daughter, starts work. Annabel does not want preferential treatment and disguises her parentage but when she lets it slip that she has had dinner with the professor and has been seeing a married man called Geoff, it is assumed that she and Loftus are having an affair. Mrs. Loftus eventually explains the truth but, to save face, Duncan tries to tell everybody about another of the professor's indiscretions.