A critically-acclaimed, two-time Oscar nominee for her roles in the films Damage (1992) Tom & Viv (1994), Richardson has also appeared in films such as Empire of the Sun (1987) (scored by John Williams), The Crying Game (1992), Merlin (1998), Sleepy Hollow (1999) (as the wife of Michael Gambon's character, and alongside Richard Griffiths), Chicken Run (2000), The Phantom of the Opera (2004) and The Young Victoria (2009).
On television, she is best known for her numerous appearances in Rowan Atkinson's Blackadder franchise, most notably as "Queenie" in Blackadder II (1986), which also featured Robbie Coltrane. She also appeared in The Lost Prince (2003). Richardson also appeared in a Harry Potter spoof with Dawn French for Comic Relief, where she played Hermione Granger and Emma Watson.
In the 2013 film Belle, she plays the mother of Tom Felton's character.
Born and raised in Southport, Lancashire, Richardson considered studying veterinary medicine or English literature, but ultimately chose to enrol in Bristol Old Vic Theatre School and to pursue acting as a career. Currently, she lives in West London with her pets, two cats and two dogs. An animal lover, she contributes to charities such as the World Wildlife Fund, the Humane Society of New York, and the World Society for the Protection of Animals.