Tom Brannick has broken bad. The surly Northern Irish police detective, played in Bloodlands by a surly James Nesbitt, stunned viewers at the end of last week’s episode by killing off Adam Cory, the innocent man who had dared ask him “Are you Goliath?” The shot to the head seemed like a shot in the arm for the series – a genuinely surprising twist that could’ve steered BBC One’s latest primetime thriller into fresh, intriguing territory. After its third (and penultimate) episode, however, that could best be described as wishful thinking.

The episode begins with Brannick and DS Niamh McGovern (Charlene McKenna) investigating Cory’s house after his sister reported him missing. Cory’s body is eventually found, and all signs point to Goliath – so the search for the long-dormant assassin resumes in full. Some deduction narrows the list of candidates down to just three suspects: Brannick, his boss Jackie Twomey (Lorcan Cranitch) and “Dinger” (Michael Smiley). Brannick also learns about Tori Matthews’ (Lisa Dwan) true identity and confronts her after a short dinner date. We still don’t know who Goliath is, though the corruption clearly extends beyond him alone. Both Brannick and Twomey have whole walk-in closets full of skeletons and are trying to stop them tumbling out. 

One of the big problems Bloodlands faces is Nesbitt himself. As his character begins to unravel, he increasingly strains to convince. Big outbursts seem forced and off-key; a short scene of him kicking a wall in frustration is genuinely so bad, it’s laughable. He overdoes the small touches, too – an overly performative reaction to a ringing phone, for instance, or a laboured squint into the distance. 

The set-up of this episode – a police investigation being manipulated from within by a corrupt officer bent on self-preservation – has made for some great television before. It has been used to impressive effect in Line of Duty, but perhaps the definitive example is in US drama The Shield, where Michael Chiklis’s malignant supercop Vic Mackey spent seven seasons scheming his way out of the clutches of justice. Working, admittedly, with flimsier material, Nesbitt is nonetheless far clumsier than Chiklis at selling the subterfuge. It’s a struggle to believe Brannick has not been caught several times over; he seems to advertise his guilt to the world with every utterance and gesture. 

It is this issue, plausibility, that is perhaps Bloodlands’ greatest failing. The police force seems to contain about three detectives and a legion of masked forensic teams. When it is revealed that the Goliath suspect list has been narrowed down to three men, it simply defies reason that the investigation would continue to be conducted by a team comprised mostly of its own suspects.

Bloodlands has tried its best to create a Line of Duty-style mystery in just three episodes – a sort of microwave-ready “Who is H?” – but it’s too daft, too melodramatic and strangely insular. “Who is Goliath?” At this point, who really cares?