<Ul> <Li> Alex Lawther as James, a 17 - year - old who believes he is a psychopath; the disturbed love interest of Alyssa . Jack Veal portrays a young James . </Li> <Li> Jessica Barden as Alyssa, a rebellious teenage girl . Initially James' intended victim but later his love interest . Holly Beechey portrays a young Alyssa . </Li> <Li> Gemma Whelan as DC Eunice Noon, Darego's police partner . </Li> <Li> Wunmi Mosaku as DC Teri Darego, Noon's stern police partner . </Li> <Li> Steve Oram as Phil, James' caring father . </Li> <Li> Christine Bottomley as Gwen, Alyssa's mother . </Li> <Li> Navin Chowdhry as Tony, Alyssa's abusive stepfather . </Li> <Li> Barry Ward as Leslie Foley, Alyssa's estranged drug - dealing father . </Li> </Ul> <Li> Alex Lawther as James, a 17 - year - old who believes he is a psychopath; the disturbed love interest of Alyssa . Jack Veal portrays a young James . </Li> <Li> Jessica Barden as Alyssa, a rebellious teenage girl . Initially James' intended victim but later his love interest . Holly Beechey portrays a young Alyssa . </Li> <Li> Gemma Whelan as DC Eunice Noon, Darego's police partner . </Li>

Who played alyssa in the end of the world