Harriet Walter is a British actress. Her film credits include Atonement, Sense and Sensibility, and The Last Duel. She has appeared in television series such as Downton Abbey, where she played Lady Prudence Shackleton; The Crown, where she played Clementine Churchill; Belgravia, Law & Order: UK, The Spanish Princess, Succession, Killing Eve, and the Apple Original series Silo.