Marcus Thurwell, you old bastard. You get, what, four mentions by name in series three? We’ve never even seen your face before today (ahoy there, Mr James Nesbitt), and now you’re our chief suspect in the search for the Fourth Man. Oh, what fools you’ve made us look. Fans have spent the last five years sizing up every inspector, sniffer dog and lampshade in Central Police as a potential H, and now we learn that he likely retired in 2005 and has been masterminding the lot while sipping a chilled Estrella Damm on the Costa del Crime. If any more names from the past turn up in series six, Ofqual are going to have to accredit an official Line of Duty qualification. Before viewers are allowed to watch the next episode, we’ll need to show evidence of having achieved a merit grade or above. For access to the finale, please submit a coursework essay on a topic of your choice (Mine: ‘A metaphorical reading of the wine glasses at Frederico’s as symbols of the moral decline in public office’.) This show demands our full and close attention. It forces us to lean in. If you hadn’t leaned in to episode five, paused it, played it back, and then Googled ‘runs of homozygosity’, you could easily have missed the real significance of Jo Davidson’s DNA revelation: Jo isn’t only related to Tommy Hunter, she’s also a product of incest. That the the revelation wasn’t given the usual ‘Wait mate, you mean Jo’s brother/dad was also her uncle/granddad?’ pleb-translation suggests that Line of Duty wants to keeps its powder dry on this one. The Jo family mystery will be solved, but not before series six is ready. First, it has a few things to say. In series six, those encroachments have multiplied and the identities of their real-life counterparts are even less obscured. The murder of Gail Vella is partly inspired by the 2017 murder of Maltese journalist Daphne Caruana Galizia – maiden name Vella – who was killed in a car bombing while investigating government corruption. This episode gave us the fictional case of architect Lawrence Christopher, which links the corrupt officers of the Sands View (or: Knowl View School, Rochdale) child sex abuse scandal to the suppression of his racist murder. The Lawrence Christopher case merges elements of the Stephen Lawrence murder in 1993 with the death in custody of Christopher Alder in 1998. Scratch the surface, and there also appears to be crossover between the fictional story of Tommy Hunter manipulating corrupt officers to protect his murderer son, and real allegations made against drug importer Clifford Norris, father to David Norris, one of two men eventually charged with the murder of Stephen Lawrence. Perhaps coincidentally or perhaps not, the officer alleged to have been in the pay of Clifford Norris, but who denied the claim, was named DS John Davidson. Depending on whether they’re noticed, these barely disguised parallels switch the purpose of series six from mystery action thriller to social commentary. The comment being made? This may be fiction, but it’s also real and utterly shameful. Look it up. Don’t let it be forgotten. That message was delivered with an emotional punch by the scene of Chloe recounting the reprehensible racist behaviour of the Lawrence Christopher officers. That was an atypically emotional scene for Line of Duty (and for Chloe, who – until last week’s shoot-out – has functioned as something of a sci-fi ship’s computer in series six, reeling out research and providing vital information). Alongside all the brain-spinning revelations in this episode, Shalom Brune-Franklin’s “How could anyone be okay?” remains the moment I can’t shake from memory. Back to the ghost train. Another week, another top cliffhanger. This time: who shot first, Kate or Ryan. If you’d rather remain in the dark about Fleming’s fate, please look away now. Gone? Take another look at the series six trailer and its as-yet-unaired scenes starring Kate for a likely answer. Come on, our girl’s a trained AFO. She knows what she’s about. As does episode director Jennie Darnell, whose industrial estate raid sequence was constructed for maximum excitement and satisfying reveals. Hearing Ted’s “Site 3” voice on that radio relay was like hearing the horn of Gondor. I stood up out of my chair. When they got that burner phone snap of Ryan, whom Kate had been dragging around like a sulky teenager, I saluted. And again when Steve made Patrick Fairbank wet himself (faking or genuine, what do we think?). There was another salute when Kate put the phone down on Carmichael, who’d slithered in to AC-12 on a slug trail of slimy sanctimony (such a great baddie). As Rohan ‘turns out not a baddie’ Sindwhani said, it’s down to you now, Ted, in whatever time you’ve got left. Two more episodes. Keep it at full throttle.