Lydia Dryden (Lorna Rose Harris) was a villainess from "Tender Loving Care," episode 11.02 of New Tricks (airdate 25 August 2014). She was a surgeon and the daughter of fellow surgeons Monica and Hugh Dryden, as well as the sister of Katia Dryden.
Lydia was the episode's murder victim, as on November 10, 2010, she was out at a nightclub before she was strangled to death in her flat, with her body found 12 hours later. The investigation revealed that there were rumors of an affair between Lydia and fellow surgeon Lawrence Devlin, only for Lawrence's wife, Nicole Hunter, to debunk the rumor with a surprising reveal: Lawrence was Lydia's biological father, the result of an affair between Lawrence and Monica. It was also revealed that Lydia was suspected of stealing oxycodone, and it was confirmed by Hugh while he was interviewed by DCI Sasha Miller.
As revealed early in the episode, Katia's career in the medical industry ended when she was involved in a ski accident, which left her with agonizing leg pain. Six months before her death, Lydia turned heel and began stealing oxycodone to give to her sister for her pain, though Katia also became addicted. As Katia revealed to Sasha, the villainous Lydia committed the thefts every few weeks, but on the night of her murder, Lydia and Katia had a falling out, with the former telling the latter that she was done due to feeling uncomfortable. Because of this, Lydia was suspected, but she denied killing her sister. Another suspect came in the form of Darren Vosper, whose wife died after a botched surgery committed by Lydia and Laurence, but Lydia's killer was revealed as Lydia's cohort and co-conspirator in the thefts, Bobby Johal. Bobby helped Lydia in the thefts due to his infatuation with her, but after seeing that Lydia had a boyfriend that night at the club, he tracked Lydia to her flat and told her that he had more oxycodone for her, only to later kill Lydia when she turned him down.