Penelope Knatchbull

Penelope Knatchbull enters Prince Philip's orbit as a friend of the family and fellow carriage-driving enthusiast, sharing his love of the countryside and its rituals. Composed and quietly perceptive, she offers him easy company at a stage of life when he has less patience for formality and more need for someone who simply enjoys his presence.

McElhone plays her with a stillness that never tips into intrigue — the show is careful, and so is she, letting warmth read as warmth rather than scandal. It's a performance built on restraint, giving Philip's later years a companion whose appeal is legible without ever being spelled out.