•
Andrew Scott as Mark Nicholas; a young man who returns to his hometown of Renton following the death of both his parents in a reported suicide pact •
Martin Clunes as Len Robson; the Mayor of Renton who struggles with alcohol problems, exacerbated by the range of public relations problems he is involved with. • Avigail Tlalim as Jodie Nicholas; Mark's rebellious 15-year-old sister. Jodie's relationship with her brother is strained at first, having never known her brother throughout her life. •
Julia McKenzie as Betty Nicholas; Mark's estranged grandmother, who has occupied his old childhood bedroom in his absence. •
Charlotte Riley as Alice; Mark's first love. Mark's return troubles Alice, who eventually leaves her husband to be with him. •
Douglas Hodge as Inspector Chris Franks; an officer from the local police force who had been having a long-term affair with Mark's mother Kate. •
Gerard Kearns as Daniel; an undertaker who is sacked after dropping Mark's mother's body. He later finds work as a cleaner alongside Betty. •
Callum Turner as Ashley; Jodie's
bad boy boyfriend. A troubled teen and reckless boy racer, Ashley is much more complicated than he first appears. •
Goldy Notay as Shireen; the Deputy Mayor of Renton and assistant to Len Robson. She is serious and ambitious, and often struggles to deal with Len's erratic behaviour. •
Sam Troughton as Jeff; an old friend of Mark's. •
Kelly Adams as Lucy; an old friend of Mark's. •
Aisling Bea as Carly; an old friend of Mark's. •
Toby Regbo as Harry; a scholarship pupil who was Jodie's boyfriend. • Jon Foster as Karl; Alice's husband, with whom she has had a child, Sophie. ==Episodes==