There’s an early episode of The Simpsons where, with the plot seemingly resolved partway through the episode the family gathers on the sofa. “Everything really wrapped up nicely,” declares Homer with satisfaction; “And much quicker than usual” he adds, with a post-modern awareness of how TV works.

I mention this only because it’s how I felt during part four (of six) of Prime Suspect 1973 when the cops knock off early to celebrate having charged drug dealer ‘Oz’ with the murders of not just Julie-Ann Collins but also her boyfriend Eddie. It seems very premature, not to mention convenient, to declare ‘Oz’ the guilty party – although, to be fair, with a witness, some fingerprints, and compelling evidence in the form of the rat poison used to kill Eddie, it’s not an unreasonable assumption. The viewer only suspects he’s not the killer because we know there are two more episodes to go.

For this week, however, the certainty that ‘Oz’ is guilty helps sway Jane’s conscience when she covers up the vicious beating given to him by DS Gibbs. Unsure whether or not it is the right thing to do, nevertheless she ultimately tows the party line and tells AC-10 (anybody hoping for a surreal crossover with Line of Duty’s AC-12 will have been sadly disappointed) that Gibbs struck just the one blow, in self-defence, and that any other wounds were caused by ‘Oz’ landing on a radiator. Much is made of Jane’s uncertainty over what to say and do, and with two episodes to go I won’t be particularly surprised if she later changes her mind and tells AC-10 the truth after all.

With the two murders solved (allegedly) there’s little for the cops to do except repair to the boozer – in Jane’s case it’s only a brief stopover before heading back to her new digs at the station house. Given that the officer in charge there has only one rule (“men are not allowed on the women’s floor and vice versa”) and given that she left home because of her mother’s prissy concerns that she might be “having relations” with her senior officer, there’s a certain irony to the fact that she’s not been there twenty-four hours before DI Bradfield is through the door. (Feel free to insert a seventies-style joke about taking down her particulars here.)

Despite expectations, we don’t see any ‘morning after’ recriminations, nor any sign that the case against ‘Oz’ is anything less than watertight. Which is all very nice, but rather undramatic. So apart from the cops having covered up a brutal assault on their prisoner; and the fact that Jane’s mother knows they’ve lied about it; and the Bentley boys’ imminent bank job; and the final shot of Julie-Ann’s missing necklace lying on the floor of their lock up…

Apart from all that, full credit to the police for having wrapped everything up so nicely, and much quicker than usual. Efficient, but alas ever so slightly unexciting.

Aired at 9pm on Tuesday 23 March 2017 on ITV.

Buy the complete original Prime Suspect series box set on Amazon here.

What did you think of this week’s episode? Let us know below…