Nicola Walker (born 15 May 1970) is an English actress, known for her starring roles in various British television programmes from the 1990s onwards, including Ruth Evershed in the spy drama Spooks from 2003 to 2011. She has also worked in theatre, radio and film. She won the 2013 Olivier Award for Best Supporting Actress for the play The Curious Incident of the Dog in the Night-Time, and has twice been nominated for the BAFTA TV Award for Best Supporting Actress for the BBC drama Last Tango in Halifax.
Walker was born in Stepney in the East End of London and has an older brother. She attended Saint Nicholas School, Old Harlow, and Forest School, Walthamstow, and undertook acting classes from age 12 to speak to boys. Interviewed in 2014 by The Guardian, she said, "I was really encouraged by my mother. My dad thought it was a ridiculous thing to do."
Walker then attended New Hall, Cambridge, where she started her acting career with the Cambridge Footlights. Her contemporaries included Spooks writer David Wolstencroft and comedian Sue Perkins, who were all part of the 1990 national tour. Perkins, then an older undergraduate, was assigned to be her "college mother", although Walker later said: "She was the worst college mother I could have had .. They’re meant to hold your hand. She asked to borrow my bike, got drunk and I never saw it again." Walker acted on stage as Perkins's stooge and years later their partnership was resumed when Perkins cast Walker in her sitcom Heading Out.