Ncuti Gatwa The Doctor Actor Millie Gibson Ruby Sunday Actor Jemma Redgrave Kate Lethbridge-Stewart Actor Bonnie Langford Melanie Bush Actor Susan Twist Susan Triad Actor Yasmin Finney Rose Noble Actor Genesis Lynea Harriet Actor Lenny Rush Morris Gibbons Actor Alexander Devrient Colonel Ibrahim Actor Jasmine Bayes Corporal Sullivan Actor Anita Dobson Mrs Flood Actor Michelle Greenidge Carla Sunday Actor Angela Wynter Cherry Sunday Actor Sian Clifford Kind Woman Actor Aidan Cook The Vlinx Actor Nicholas Briggs Voice of the Vlinx Actor Russell T. Davies Executive Producer, Writer Julie Gardner Executive Producer Jane Tranter Executive Producer Joel Collins Executive Producer Phil Collinson Executive Producer Vicki Delow Producer