Professional Opinion is the 1122nd episode of The Bill.
P.C. Stamp and W.P.C. Keane go to the scene of an argument between a man and a woman outside a flat on the Jasmine Allen estate. The man tells them that his wife is inside but that the woman won't let him speak to her. The woman tells them that his wife doesn't want to see him.
They calm the situation down and persuade the man to leave. As he is escorting him away, the man tells Stamp that his wife hasn't spoken to him since their son's funeral. She blames herself for his death, as he died after taking some of her methadone, which he had mistaken for a fizzy drink. The man doesn't blame his wife: he blames her doctor who, he claims, is prescribing stronger than recommended doses to patients.
Later, the man is arrested for trying to attack the doctor. D.S. Daly and D.C. Skase investigate and in doing so almost ruin a drug squad case. D.I. Deakin gives Daly a ticking off for failing to check P.N.C. for interest markers, then tells him to assist D.C. Dave McGovern in his investigations in the hope that they can both still get a result.