Sarah Gallagher is the deceased wife of Neville and mother of Frank. Sarah was incredibly close to her son and the two of them shared a strong dislike of Neville. Sarah would often defend Frank from his father, sometimes making excuses for him. At one point she even claimed Frank was autistic to spare him his father's wrath, which Neville believed, until, in his words, "[he] called [him] a cunt in suspiciously fitting circumstances".
She was a career trade unionist and was elected councillor for Denton South on a platform of support for single parents, defeating the overconfident favourite candidate, Vic Feather. According to Episode 10 of Series 6, she also fought hard for improvements to education. In Episode 1 of Series 2, it is suggested by Frank that his mother's career was put on hold when she gave birth to Frank, to the delight of his father, Neville.