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,
Polly (Doctor Who) created Ben and Polly in 1966. What happens to Polly after her return to Earth is not certain. The Doctor seems to think that Ben will become an Admiral and that Polly will look after Ben, but it is unclear if this is a prediction or simply wishing them well. In "The Sarah Jane Adventures" story "Death of the Doctor" (2010), Sarah Jane mentions that Polly is now working at an orphanage in India with Ben. On 23 July 2017, the first trailer for the 2017 Christmas special episode, "Twice Upon a Time", was shown during the 2017 San Diego