Dandelion Dead (1994) (Episode 2, Part 2)

Part 2 of 2 of a period crime drama from 1994, based on a true life case. After the death of his wife, Herbert Armstrong feels confident to introduce his mistress to his children. But eldest daughter Eleanor mistrusts him, and he begins to suspect that rival lawyer Oswald Martin in the firm opposite his office suspects him. So he decides that what worked once before can do so again, and soon Oswald begins to feel ill...

Starring Michael Kitchen, David Thewlis, Lesley Sharp, Bernard Hepton, Don Henderson, Chloe Tucker, Diana Quick, Peter Vaughan, Robert Stephens, Roger Lloyd Pack, Lucy Jenkins and Alexandra Milman. This is from a DVD I had of the drama, which was broadcast in February 1994, but one that sticks in the mind.