"Accused" Stephen's Story S02E03 (TV Episode 2012) with Robert Sheehan

Peter Cartwright engages Charlotte,a nurse,to tend his dying wife Katherine and,several months after Katherine's death,begins to date her,finally marrying her. Whilst Peter's younger son Dom gets on with her his brother,17-year-old Stephen,becomes obsessed with the idea that Charlotte killed his mother and is now trying to poison him. He hears voices from the television warning him but refuses to accept that he needs psychiatric help. Indeed when he goes on trial for trying to kill Charlotte,he clings to his story that it was self defence to prevent her killing him and Dom.