B leak. Unpleasant. Prurient. These three words, based on the opening episode alone, could be applied to Half Man , Richard Gadd ’s much-hyped follow-up to Baby Reindeer , his semi-autobiographical stalker drama on Netflix. By the end of this six-part BBC / HBO drama, two more stand out: trauma porn. Never before have I seen a TV show this smugly grim – such a relentless exercise in self-punishment that even watching it feels like an act of nihilism. Spanning four decades, it’s the story of two siblings bound together by circumstance, violence and the secrets each keeps from the other. Take a scene in episode two. Hoving in with a horrific sense of foreboding, the air thick with menace, it left me gasping. Two brothers from another mother, the volatile Ruben (Stuart Campbell) and the timid Niall (Mitchell Robertson), are at the latter’s student flat. Alby (Bilal Hasna), with whom Niall has just hooked up, is about to tell Ruben his younger sibling is gay.…