The Liver Birds and Series 1 starred Pauline Collins as Dawn and Polly James as Beryl Hennessey. In Series 2, Nerys Hughes debuted as Sandra Hutchinson, replacing Dawn for the rest of the programme's run. The Beryl-and-Sandra pairing is generally regarded as the programme's best period. Beryl was the more 'common' one, while Sandra was soft-spoken and more refined, due to the influence of her snobbish, overbearing mother (Mollie Sugden). Carla Lane drew on her own mother for the character – "Mrs Hutchinson, I think she was my mother. I'm sure she was my mother". Beryl's 'common' mother (the Hennesseys live in Bootle,
The Liver Birds Stars", a programme shown annually on Christmas night, when leading BBC performers appeared in short versions of their series, typically 5–10 minutes long. Carla Lane became sole writer for the fourth series. She felt it was now time for the Liver Birds to start thinking about longer-term relationships with men. John Nettles played Paul, Sandra's (frustrated) boyfriend, and Jonathan Lynn played Robert, Beryl's boyfriend. "I always wanted The Liver Birds not to be too keen about marriage—not to down it—but not to be out to get a boyfriend to marry," Lane explained. Beryl's mother (Sheila Fay) voiced the critical view: