A downtrodden wife tries to leave her abusive husband but in the course of a confrontation ends up stabbing him in front of her young son. The case makes front-page news, stirs a moral debate and prompts a spike in donations to domestic abuse charities. The thing is, the story is not for real. Since the tale of Helen and Rob Titchener, characters in the BBC’s radio soap opera "The Archers", reached its violent climax in Sunday evening’s episode, a lively public response has shown the power of this peculiarly British cultural institution.