Nancy Skerrett

Nancy Skerrett arrives at Buckingham Palace as a lady's maid, sharp-eyed and quietly ambitious in a household run on rigid hierarchy. She is good at her work and knows it, watching the below-stairs politics with a shrewdness that outpaces her lowly station, hungry for a life bigger than starched aprons and orders.

The show could easily have left her as scenery below the grand staircase, but Nell Hudson plays Skerrett with a restless intelligence that makes her feel like the story's other engine, not just its downstairs mirror. Her scenes carry real stakes precisely because she wants something and is clever enough that you believe she might get it.