Line of Duty series 5 recap: 8 major revelations in that EXTREMELY dramatic episode 4

Here are the eight big questions we're still puzzling over...

1. Did Ted give the order to kill John Corbett?

Episode four ends DRAMATICALLY with undercover officer John Corbett (Stephen Graham) lying in a pool of his own blood, his throat slashed wide open, while Lisa McQueen (Rochenda Sandall) stands over him and snarls: "You're a rat, John." And so another major Line of Duty guest star bites the dust...

But there is a big unanswered question left for fans to puzzle over: does Lisa work out the truth by herself, or does Superintendent Ted Hastings (Adrian Dunbar) directly order the hit? And – if so – is he 'H'?

• LONG READ: examining all the evidence against Ted Hastings

After all, it is Ted who swoops in and takes over when AC-12 is messaging Lisa and John under the pretence of giving instructions from 'H'. He then takes things entirely into his own hands, confidently typing out messages while DI Kate Fleming (Vicky McClure) and DS Steve Arnott (Martin Compston) shoot each other perplexed looks. "I need you to bring all this to a close," he writes – but when John asks "What do you mean?" he speaks aloud, asking rhetorically: "What do I mean?" before disconnecting the call.

It's not clear what the purpose of this phrase could be, unless it's a signal to Lisa. Was Ted acting as 'H' and telling her to kill the "rat"? Adding to this theory is the fact that, as soon as she's out of sight, Lisa drops the "tough guy" exterior and starts crying. If she didn't want to have John murdered, perhaps that means she's acting on the instructions of someone else?

HOWEVER, it's not as cut and dried as all that.

It's entirely possible that Lisa figured things out all by herself, and is acting on her own initiative rather than on Ted's words. It's also possible that she consulted with the real 'H' (if he or she is not Ted Hastings) after becoming suspicious about John, and received orders directly from him (or her) to kill John.

As we see in the episode, Lisa recognises Steve Arnott from the photo taken by Terry as AC-12 raided Kingsgate Printing Service, commenting that he “works for the same outfit as Maneet Bindra." She quickly realises that Hargreaves was not the one doing the double-crossing, telling Miroslav and Ryan: “They’ve been onto us since well before we put Hargreaves on the Eastfield job. We never told Hargreaves about the print shop, the leak came from somewhere else. We’ve got a rat.”

Suspicion obviously falls on John, who never gave a good explanation for why he evacuated the print shop HQ before the raid. Lisa has been giving him funny looks for a while now, and has been fielding his questions about the true identity of 'H'; now John starts to blow his own cover by questioning Lisa over whether she really, truly wants to be involved in people trafficking and the sex trade. It is entirely possible that Lisa worked things out and set up the trap for John Corbett all by herself.

ALSO, if Ted Hastings is 'H', he has known since episode one that John Corbett is an undercover cop. Why on earth would he leave John embedded for so long if he knew the truth? Surely he'd have blown his cover much, much sooner before he managed to get so much information to Steve and Kate?

2. Does “definately” confirm Ted Hastings is 'H'?

Line of Duty fans were right to suggest that the misspelled word "definately" was a clue, because – BINGO! – it makes a highly-significant reappearance in episode four.

Last time around, we saw John Corbett and Lisa McQueen receiving instructions about a planned raid on a police facility via instant messages from a senior crime boss, presumed to be 'H'. “Eastfield depot is definately high risk," 'H' wrote.

Now, with the help of cybercrime expert Amanda Yao (Rosa Escoda), AC-12 is able to mimic the connection from 'H' and kid both McQueen and Corbett into thinking they're talking with the corrupt officer himself (or herself). It's worth emphasising that they only have access to the metadata from previous conversations, so they have no idea that 'H' previously misspelled the word "definitely". And yet, when Ted Hastings sits down and starts typing out messages, he writes: "I can definately pull the right strings," a clue that won't go unnoticed among Line of Duty viewers.

Of course, Ted is not the only person in the world ever to misspell "definitely." But surely this is more than a coincidence? Is Ted actually the person who has been giving the OCG their instructions?

3. Why did Ted visit Lee Banks?

Episode four tantalises us with a brief clip of Ted Hastings' visit to Blackthorn Prison, Line of Duty's one and only jail – which by now is practically bristling with bent coppers and their accomplices.

"Sit down, fella. This b***ard's got a thing or two to say to you. Trust me – you'll be glad you did," Superintendent Ted Hastings instructs Lee Banks (Alastair Natkiel), in a tone of voice entirely different to the way he usually speaks. Is that a glimpse of the 'real' Ted Hastings?

Sadly we don't get to hear what he says to balaclava gang member Lee, but what is Ted up to? Why hasn't he told Kate and Steve about his visit to the prison? Why does he appear to have someone else driving the car while he sits in the back? And what information does he have to offer Lee?

4. Who is Anne-Marie?

AC-12 makes a breakthrough after gaining entry to John Corbett's apartment: finally, they have DNA and fingerprints. And although Operation Peartree did their best to hide all information on the database before John went undercover, not everything is 100% gone – because there is a fingerprint match on the database.

We discover that John was actually adopted at the age of 10 in 1989 by the Corbett family. His adoptive mother's maiden name was McGillis, and as Tatleen suggests, his adoptive mother was probably a close relative of one of his birth relatives – because his name at birth was John McGillis.

John was born in Belfast, and his father was Anthony Patrick McGillis, who died in 1984; his mother, Anne-Marie McGillis, died in 1989 – "hence Corbett's move to Liverpool, and the adoption."

But what is the story behind Anne-Marie's death? Or is she still alive? And with John born in Belfast, is there a connection to our very own Ted Hastings?

Adding to the mystery is a phone call between John and his wife Steph, who reports a visit from Kate and Steve. "They was asking about Northern Ireland," she tells her husband, shakily. "They was even asking about family over there."

"Well did they know anything? Anything about my mum, and anything?" John responds, while Steph asks: "What's this all about? Do they know about Anne-Marie?"

It seems we've only scratched the surface of John Corbett's backstory...

5. Does Ted Hastings have a secret about Northern Ireland?

Ted's estranged wife Roisin Hastings says that she didn't see the face of the man who broke into her house, although viewers saw it was John Corbett who put on the balaclava and cut the chain on her door. But she does tell Ted: "He was from back home... he spoke with a Belfast accent. He said you'd know why he’d done it, he said you’d know what you've cost him."

We then hear the voice recording John plays down the phone to Steve, in which a bloke with a Belfast accent (John) tortures and questions Roisin. Why the injuries to her wrists, knees and ankles, Steve asks. Clearly distressed, John answers: "No. It's not going to come from me. It'll just be wrote off as a lie, same as it always was. No, it's got to come from him."

Earlier in the episode, Steve also commented to Kate: "We all know her injuries are classic paramilitary punishment wounds." And later, John tells Steve: "I assaulted your gaffer's wife."

So at this point, we have to ask: did Ted have some involvement in the Troubles in Northern Ireland? Did he harm John's family? And what do we really know about Ted Hastings?

6. What did Ted do with the money? What is Mark Moffatt up to?

We've been VERY suspicious of Mark Moffatt ever since he reappeared in episode two, offering Ted a too-good-to-be-true scheme to recover his money from his disastrous Kettle Bell Complex investment in Ireland – and now we find out that our hunch was well-founded. Having loitered in the lobby of Ted's hotel, Moffatt stops the AC-12 boss on his way up the stairs and thrusts a brown padded envelope into his hands, insisting it's vital information for him to study.

Inevitably, the envelope turns out to be packed with brand-new £50 notes. Ted takes them out and studies them while drinking a large glass of whisky at the desk of his shabby hotel room, looking troubled.

As widely suspected, Moffatt must be trying to recruit him to join the network of bent coppers. It looks like he's taking the same approach the balaclava gang has used with Vihan Malhotra and so many others: find out something damaging about a police employee, collect information, give them money, and – once the person is entirely compromised – blackmail them into cooperation. But will Ted be stupid enough to fall for it? Will he keep the money or will he tell his police colleagues?

Another crucial thing to note: the overtures from Moffatt seem to suggest that Ted isn't already bent. Which – along with the fact that he's completely broke – would suggest he is not 'H' after all...

7. Why did Ted give the lethal order – and was the Palisade Shopping Centre meeting a ruse?

Superintendent Ted Hastings seems incredibly keen for Steve to kill John Corbett. Is that a professional decision based on analysing all the risks, benefits, and dangers of the situation? Is it about retribution for Roisin Hastings' torture? Or is there another reason?

"The order is Fahrenheit. Repeat, the order is Fahrenheit," Ted says – though Kate disagrees and Steve actually disobeys him. Does Ted want to stop Steve (aka "the wee gobs***e") from learning more damaging information about corrupt officers? Does he need John Corbett dead before he gets to the truth?

Steve eventually gets details of John's meeting with 'H' – although it never takes place. Perhaps because it was a red herring from Lisa, or perhaps because 'H' knows that armed cops would be watching – which he'd know, if he was actually Ted Hastings. After all, John had warned Steve: “Be careful who you tell – if it gets out, you’ve got a leak."

Both Kate and Steve seem extremely suspicious of Ted's motives, with Steve telling the gaffer: "With respect, sir, I dispute the lawfulness of your order." And Kate asks for guidance for her write-up, telling her boss: "Your Fahrenheit order was irregular."

In response, Ted cites Common Law, Section Three of the Criminal Law Act of 1967, and Section 117 of the Police and Criminal Evidence Act of 1984, which is an extremely Ted Hastings response.

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8. Is that Jackie Laverty in the freezer?

"Christ! I forgot! How long she been there?" says Miroslav (Tomi May) cheerily as he opens Terry's freezer on the hunt for beers – and finds a dismembered human body instead. The plastic-wrapped corpse is, of course, none other than Jackie Laverty (Gina McKee) who met a grisly end in Line of Duty series one.

Back then, the balaclava gang was led by Tommy Hunter (Brian McCardie). The OCG's top dog had corrupt businesswoman Jackie killed, dismembered, and placed in cold storage with evidence to incriminate DCI Tony Gates (Lennie James) as a means of blackmailing him. But since Tony's death, Jackie has been languishing forgotten in Terry's kitchen.

As a vulnerable adult with Down's Syndrome, Terry (Elliott Rosen) has been preyed on by Ryan and the balaclava gang who have moved him from his original home on the council estate into a flat opposite their HQ at Kingsgate Printing Services, so he can keep an eye on comings and goings.

But while the contents of the freezer were definitely jostled around during the move, it's clear those are still Laverty's legs...

Line of Duty continues on Sundays at 9pm on BBC1