The Liver Birds was a sitcom based in Liverpool, UK about two twenty year old girls sharing a flat together. One of the girls was called Sandra (she was the posh one and was very well spoken) and the other one was Carol (who was more working class and spoke with a broad Liverpool accent).
Carol had a brother who would call in from time to time and talk non-stop about his rabbits. Sandra had a mother who did not really get on with Carol and thought she was too common. Sandra always called her mother "mummy".