Trial & Retribution XVI: Kill the King (1)

The dead man this time is a friend of the house. Jonathan Carlisle, a well-known paediatric surgeon and a mate of Mike Walker's, is found murdered, and the first suspect practically introduces himself. Gary Webster blamed Carlisle for the death of his daughter Amber, who died during an operation, and he had been stalking the surgeon for months, long enough that Carlisle had taken out a restraining order. Grief with nowhere to go, curdling into obsession. It's an old story and the show tells it well.

But the obvious suspect is only the beginning. Neelah Shahjani comes forward to say she found the body, and mentions the detail that changes the temperature of everything: Carlisle had a needle in his arm. And then there's Dr Lawson, who is almost too helpful, volunteering a video he says proves the hospital bore no blame for Amber's death. When a man starts producing evidence nobody asked for, you start wondering what he's so keen to close the book on. Two doctors drift into the frame while Webster runs, and Connor has to work out whether she's chasing a killer or watching one being framed.

Before she can question Webster, he bolts. What follows is a tense cat-and-mouse across London that ends at the zoo, of all places, with the police closing in and the outcome genuinely uncertain as the credits arrive. John Lynch plays him as neither monster nor martyr, just a father the system failed twice over.

Christian Spurrier wrote it, Gillies MacKinnon directs, and Victoria Smurfit carries the inquiry with Walker kept at a painful distance — this one is personal for him, and he has to watch someone else run it. The supporting cast is strong: Brid Brennan as Gemma Webster, Shelley Conn as Neelah, Ben Miles as Adrian Lawson, Joanne King as Sister Claire Jenkin, plus Vince Leigh's Palmer and Dorian Lough's Satchell.

A gripping first half, and the hospital setting gives it a moral murk most procedurals won't touch.