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,
Doctor Who (series 4) disappearing from planet Earth and stories driven by a missing or lost planet. Executive producer Russell T Davies stated in the same feature that the series' finale had been planned for three years previous to its airdate. The regular series focuses heavily on Donna: David Tennant stated that the "whole thirteen weeks is Donna's story ... why she's with the Doctor again is the subtext", and producer Phil Collinson cited Donna as a "fresh dynamic" for the fourth series. "Doctor Who Magazine" gradually revealed writers for the series alongside episode announcements. First-time writers for the programme included James Moran, co-writer