The plot thickens. The theories proliferate. The fans can't wait for next Sunday.

There might not have been any sex, sudden deaths or shock explosions this week but there were twists, deepening conspiracies and plenty of intrigue as Jed Mercurio left his hit thriller beautifully poised for its grand finale.

Here are all the talking points from the penultimate episode…

The bomb wasn’t in the briefcase

Well, that will teach viewers - not to mention the police - for following Mercurio’s narrative misdirection and obsessing about the contents of the metal briefcase carried on-stage by aide Tahir Mahmood (Shubham Saraf), after being inspected by protection officer Sgt David Budd (Richard Madden).

Instead, the bomb that killed Home Secretary Julia Montague (Keeley Hawes) was planted under the St Matthew’s College stage. Which, if you’ll permit us a little self-backslap, we predicted a full fortnight ago . It was sealed in an airtight container to put off sniffer dogs and operated by a pressure sensor.

The police’s latest theory is that Montague somehow managed to avoid setting off the bomb, hence it was Tahir’s presence on-stage that triggered it. Was it also activated remotely and if so, by whom? “I’ve got my suspicions,” snarled DCI Deepak Sharma (Ash Tandon), who has long had it in for our hero Budd. Probably jealous of his flexing jaw muscles and brooding stare.