Television:
* Men Behaving Badly (1992-1998) - as Dorothy "Dot" Cotton
* Heartbeat (2001-2006) - as Gina Ward
* Jonathan Creek (1997-2016) - as Polly, Jonathan Creek's girlfriend
* The Vicar of Dibley (1994-2007, 2013, 2020) - as Miss. Alice Tinker
* Life Begins (2004-2007) - as Gina Ward
* Rosemary & Thyme (2003-2010) - as Rosemary Boxer
* Doc Martin (2004-present) - as Louisa Glasson
* Call the Midwife (2012-present) - as Sister Monica Joan
* The Tunnel (2013-2016) - as DS Elise Wassermann
* Decline and Fall (2017) - as Mrs. Fothergill
* The Good Karma Hospital (2017-present) - as Lydia Fonseca
* Murder, They Hope (2019) - as Barbara
* Death in Paradise (2021) - as Catherine
* The Crown (2022) - as Princess Margaret
* The English Game (2022) - as Mrs. Margaret Crouch
Films:
* The Importance of Being Earnest (2002) - as Cecily Cardew
* The Importance of Being Earnest (2002) - as Cecily Cardew
* The Girl in the Cafe (2005) - as Jenny
* The Greatest Game Ever Played (2005) - as Alice Vardon
* Miss Pettigrew Lives for a Day (2008) - as Mrs. Elmsworth
* The Boat That Rocked (2009) - as Beverley
* The King's Speech (2010) - as Carol Thatcher
* The Adventures of Tintin: The Secret of the Unicorn (2011) - as Mrs. Thompson (voice)
* Hyde Park on Hudson (2012) - as Daisy Benton
* Saving Mr. Banks (2013) - as Dame Wendy Darling
* The Guernsey Literary and Potato Peel Pie Society (2018) - as Dorothy Dinnage
* The Personal History of David Copperfield (2019) - as Mrs. Gummidge
* The Electrical Life of Louis Wain (2021) - as Miss Henrietta Wain
* The Unlikely Pilgrimage of Harold Fry (2023) - as Maureen
Other Notable Work:
* The Archers (1999-present) - as Jill Archer (radio series)
This list includes only a few of her projects, as she has a very extensive and varied career spanning decades.