Big Boys' Rules (2) (master); Wikipedia "Big Boys' Rules (Part Two)"; IMDb "Big Boys' Rules: Part II"

The second half of the season's climax opens at Harris's funeral, with Clark, Naylor and Dilke in the congregation and Trevor Bull there too, watching the proceedings. The official report clears Special Branch of the informant's death, and Clark is quietly told to ease off Deakin. Nobody expects him to.

J. C. Wilsher wrote both parts, Richard Standeven directed them, and this one delivers on the setup. Clark puts the funded works at Bull's house to the man himself, hoping for dirt on Deakin, and gets nothing. But then, instead of Mo's promotion party, he goes to a safe house to see Angela Berridge and finds Deakin there, along with the news that Deakin has been freelancing for MI5. The threat is simple: if Clark goes down, so does Angela.

Bull, meanwhile, has dug up a pump-action shotgun and used it on a police officer who came to investigate. There is history here worth knowing: Bull was himself the victim of a police shooting years earlier, which gives his violence an origin the episode doesn't labour. Deakin, ignorant of that, blackmails Clark into fixing him, and only after Clark leaves does Deakin realise he's going to need the man he just threatened. There's a lovely coldness to that final beat: two predators circling each other and both knowing the other one's teeth.

Frank Harper's Bull and David Morrissey's Dilke close out the arc, and Tony Doyle's Deakin remains the series' best villain, all reasonableness and menace in the same sentence. Clark ends the season cornered, and the show leaves him there. Big boys' rules, after all, are made by the biggest boys. It went out as the season's most-watched episode, and the finale earns its audience by paying off threads two seasons in the winding. The safe house scene is the pivot, a quiet room where the people who decide the ending say their piece, and it's all the more tense for being so still. Deakin's blackmail is delivered almost politely, which is the most frightening version of it.