She portrayed Edna Hawkins ("Mrs H") on Shelley (1979–1982), Jane Travers in Clarence (1988), and Miss Lucinda Davenport in Last of the Summer Wine (2003–2010).

During the 1970s she had significant roles in comedy sitcoms including Six Dates with Barker, Coppers End (1971), and 1977's Odd Man Out with John Inman playing his half-sibling.

[12] Tewson's most prominent role was as Elizabeth "Liz" Warden, neighbour and reluctant confidante of social wannabe Hyacinth Bucket in the comedy series Keeping Up Appearances, written by Roy Clarke.

[14][better source needed] In 2009, she played Iris in the radio drama Leaves in Autumn written by Susan Casanove, produced by the Wireless Theatre Company.

[15] Other television appearances included an episode of Heartbeat ("Closing The Book", 2002), and as competition judge Samantha Johnstone in the mystery drama Midsomer Murders ("Judgement Day", 2000).

She appeared in two episodes of Doctors as kleptomaniac Audrey Wilson ("Now You See It...", 2009), and as Marjorie Page, a woman in the early stages of Alzheimer's disease ("The Bespectacled Bounder", 2012).