Episode 3

Two attacks have left the capital jumpy, and David Budd is meant to be the man standing between Julia Montague and the next one. But she is not making it easy. Her counter-terrorism bill is moving through Parliament, and every vote sharpens the rivalries around her.

A stranger calling himself Richard Longcross hands her a tablet with instructions for reaching encrypted material. Budd can find nothing on him, which is its own kind of answer. Montague corners the Prime Minister at Chequers, and nobody learns what was said. The counter-terrorism detectives Sharma and Rayburn interview Budd about the sniper and do not try to hide their scepticism. RIPA 18 passes its third Commons vote. Mike Travis, the counter-terrorism minister, takes his worries about Montague and MI5 to Roger Penhaligon. Whitehall is quietly tearing itself apart while the Home Secretary keeps smiling.

The personal thread snaps in the middle of it all. A PTSD episode ends with Budd's hands around Montague's throat. She keeps her distance afterwards, then, before the big speech, tells him she knew his children's school was flagged as a possible target, and says she wants him beside her by choice. It is a confession as much as a request, and the closest thing to honesty either of them has managed. Just before she goes on, Budd spots her PR adviser Tahir Mahmood waiting outside the auditorium. He checks the briefcase and waves him in. Seconds later the bomb goes off.

Jed Mercurio wrote it, Thomas Vincent directed, with Sophie Rundle's Vicky, Michael Shaeffer's Longcross, Stuart Bowman's Hunter-Dunn, Vincent Franklin's Travis and Nicholas Gleaves's Penhaligon doing the heavy lifting around Madden and Hawes.

You can argue with plenty in this episode, but the timing of that final beat is cruel and exact. The show has been building since episode one to a single question, who gets close enough to hurt her, and it delivers the answer without ceremony.