She was born at Birkenhead in Cheshire, and educated at the University of Liverpool, going on to act at the Liverpool Playhouse. She went on to study at the Bristol Old Vic's theatre school. She appeared in many stage productions, including musicals, and made her Broadway debut in 1966. Her numerous television appearances, including roles in Coronation Street and several BBC drama serials, failed to make her a household name until the 1980s, when she appeared, amongst other things, in Victoria Wood's comedy series, and Alan Bennet's Talking Heads series of short plays.
It was in 1990 that she first played the comic role of Hyacinth Bucket, an originally working-class woman with social pretensions (for example, she insists on pronouncing her surname "Bouquet"). In 1996, she took the lead in another long-running series, this time a drama, Hetty Wainthropp Investigates. She has also played several real-life characters on television, including Barbara Pym and Hildegard of Bingen.