Line of Duty fans across the nation were left on the edge of their seats as they watched the nail-biting series finale tonight and counted down the minutes until the mysterious antagonist 'H' was unmasked.
As the show kicked off, seasoned fans took to social media in their droves to share their reactions as officers of the police anti-corruption unit AC-12 drew a step closer to the identity of the elusive 'fourth man'.
The series, which hit more than 11 million tuning for the current series' penultimate episode, will see the puzzle over journalist Gail Vella's murder solved and the elusive 'fourth man' colluding with the organised crime group (OCG) revealed.
During the show, DI Steve Arnott, played by actor Martin Compston, was finally called in for a meeting with Occupational Health, who noted that while he had not broken the law through his excessive painkiller use, he would have to surrender his firearms licence.
As the team from AC-12 tried to unravel the mystery surrounding journalist Gail Vella's death, they also found a strong box hidden under the floor of the OCG's workshop.
As the show began, one user wrote on Twitter: 'Why does Steve look like a mortgage broker from Nationwide.'
While another added: 'Okay who else is ready for this? #Line of Duty.'
Another Line of Duty fan wrote: 'Imagine being the actor who plays 'H' waking up tomorrow to your face on the front of every tabloid newspaper in the UK.'
Elsewhere actor Sanjeev Bhaskar wrote: 'So final episode of this series of Line of Duty in just over an hour so I'll say in advance...that's exactly what I thought was going to happen.'
Yesterday fans of Line of Duty described the wait for tonight's finale as 'torturous', with around 12 million viewers planning to spend their Bank Holiday Sunday finding out the identity - finally - of evasive criminal 'H'.
Social media was awash with people posting about their excitement, with many saying the nation's bank holiday day off tomorrow would offer tense viewers 'a chance to recover'.
The cinematic finale is even being screened in beer gardens across the country by landlords also transfixed by the show.
Twitter saw hundreds of memes being shared as the build-up reached fever pitch with #lineofdutyfinale and #lineofduty trending on Twitter on Sunday morning.
While many were using the familiar faces of the main characters - including DI Kate Fleming (Vicky McClure), Superintendent Ted Hastings (Adrian Dunbar) and DI Steve Arnott (Martin Compston) - others shared photos of how H appeared to be infiltrating their bank holiday.
@DuckRecordings offered up a snap of his daughter's birthday balloons rearranged to say 'Happy H Day'.
Elsewhere, @RebeccaMarett was getting subliminal messages from the way her eggs were lined up in the box - spelling out H.
She wrote: 'Everything's pointing to #LineofDutyFinale tonight. #breakfast'
@GemmaC_PR added after spotting a pink floral H in her daughter's bedroom: 'Mother of god, you know you're excited about the #LineofDutyFinale when you're seeing clues in your own daughter's bedroom.'
@JessCiara wrote that putting the biggest TV event of the year out on a bank holiday was thoughtful of the BBC, saying: 'Excellent work by the BBC to schedule the #LineofDutyFinale on a bank holiday weekend.
'The nation will need tomorrow to recover. I’m taking to the streets in celebration if we find out who H is. #LineOfDuty'
One Line of Duty superfan even created a huge evidence board in a bid to finally unmask the mysterious villain 'H'.
Mother-of-three Katie Rogers has watched each episode of the current series five times at least, plus as many as 50 separate viewings of each of the show's previous episodes.
She claimed rewatching them so many times enabled her to find new hints and clues that many just watching live may have missed.
The 40-year-old from Winterborne Kingston in Dorset, told the Times: 'The show is so great and interactive.
'Over the last 12 months [of lockdowns] we've got more and more disconnected and not been able to see people and this has brought us back together.
'I think I speak to my family twice as much since the show started compared to before.'
She shares a passion for identifying bent coppers with her parents, and will be watching the finale with them tomorrow night.
Many others, however, will be heading to pubs, who are offering special screenings for what is likely to be ones of the biggest TV events of the year.
The Angel Hotel in Uddingston near Glasgow is not broadcasting the Old Firm derby between the two city giants, Rangers and Celtic, but has set up an 85-inch screen so it can show the drama in the evening.
Ahead of the finale, a poll found fans believe Chief Constable Philip Osborne is the most likely to be unveiled as 'H', a poll has revealed.
With seasoned viewers desperate to finally learn the anonymous villain's identity, YouGov Direct surveyed fans over who they believed was the true mastermind.
Osborne, played by Owen Teale, was the prime suspect, according to nearly a quarter of fans, with 22 per cent believing he was the individual pulling the strings.
The chief constable certainly fits the 'high ranking officer' bill, and has the power to punish anyone who fails to do his bidding.
In the last episode, it appeared as if fan favourite Superintendent Ted Hastings suspected Osborne, asking the arrested detective Jo Davidson during her interrogation if the 'fourth man' was the chief constable.
Some also suspected Osborne's 'enemies within' speech during the closing montage may go on to prove significant.
The next most popular suspect was Anna Maxwell Martin's Detective Chief Superintendent Patricia Carmichael - who swooped in towards the end of the last series to interrogate Hastings - with 19 per cent of viewers believing she was 'H'.
Elizabeth Rider, who plays Deputy Chief Constable Andrea Wise, was fingered as the culprit by 6 per cent of Line of Duty viewers, while the same proportion think that commanding officer Hastings himself was 'the fourth man' behind the series' events.
Some 4 per cent of viewers thought that newcomer Marcus Thurwell could be the criminal mastermind, and the same proportion thought it could be the show's former Police and Crime Commissioner Rohan Sindwhani.
Fans were less convinced that the series' other lead AC-12 characters, Detective Inspectors Kate Fleming and Steve Arnott were behind the plot, at 3 per cent and 2 per cent respectively.
The show's writers and cast have done well to mask the identity of the villain despite H's central role in the show, meaning nearly one in five viewers (19%) have no clue about who they could be.
It comes as star Martin Compston - who plays DI Steve Arnott - revealed the BBC drama could be coming to an end sooner than everyone thinks.
Martin - who previously revealed that executive decisions about the series are 'above his pay grade' - cast doubt on the show's future during an appearance on The Jonathan Ross Show.
In scenes due to air on Saturday's episode of the ITV show, Martin, 36, said: 'We won’t come back just for the sake of it. That’s for sure. We’ll come back if there’s a story to tell.
'If it ends well maybe sometimes it is best to leave it. But genuinely we don’t know.'
The admission comes after Martin teased that fans will get some 'big answers' during Sunday's finale, and admitted he believes it could be the 'perfect ending' to the police drama.
Speaking on the Shrine Of Duty podcast, Martin confessed that he thinks Sunday's episode could be the best way to wrap up the 'story arch' - but he refused to rule out another series.
When quizzed on whether viewers will learn who the elusive 'H' is, Martin said: 'I wouldn't quite go the Jo Davidson no comment route - but what I will tell you is I think there's a lot of pay offs coming this Sunday.
'There's a lot of big answers and it's deserved, people have stuck with us for a long time, so there comes a point where the story arch comes to an end.'
Martin also touched on whether series seven is likely, after show bosses previously claimed they believed the current season would be the last.
He said: 'We don't know [if there will be another] - that's nothing new. Jed always takes time after a series, like a couple of months.
'There's a lot of stuff above my pay grade like analytics and audience scores. He takes the emotion out of it and looks at all that.'
Admitting it could be the 'perfect ending', he said: 'It's different this year, because we have to look it in terms of, do people want us back? 10 years in you start to think of legacy, and if it goes down that well it might be the perfect ending.''But then we might go another couple of months and... what I will say is we won't do one just for the sake of doing it. Jed will only do it if there's a story to be told.'
Line of Duty: 18 questions that NEED to be answered in next week's grand finale - from why Kate and Jo fled after shooting Ryan Pilkington to what is under the concrete floor (and will we FINALLY discover the identity of H?)
Line of Duty fans were treated to yet another hour of nerve-shredding action last night, with the penultimate episode leaving its record-breaking 11 million viewers desperate for answers.
After shooting bent copper and OCG stalwart Ryan Pilkington dead, DI Kate Fleming (Vicky McClure) and DCI Jo Davidson (Kelly Macdonald) - who had orchestrated the shady meet up to 'get rid of Fleming' - went on the run, before they were caught after DCS Patricia Carmichael (Anna Maxwell-Martin) put trackers on all AC-12 vehicles.
During a tense interview scene - which ran for 29 minutes - Jo learned the sordid truth about her family history but refused to give away all she knows about the OCG and its elusive leader H when pressed by Superintendent Ted Hastings (Adrian Dunbar) - whose questions were repeatedly shut down by an increasingly shifty-looking Carmichael.
Meanwhile Marcus Thurwell (James Nesbitt) - the retired former detective chief inspector suspected of being in league with organised crime and even in the frame for being H, the corrupt officer now referred to as the 'fourth man' - was found dead at his address in Spain, leaving Hastings exasperated as time is running out before he's forced into retirement and AC-12 is disbanded.
And DS Chris Lomax seemed less than enthusiastic when Kate suggested searching under the floor at the warehouse the OCG was using to workshop firearms - so, is he hiding something, and what does she suspect?
Today the BBC released a teaser trailer promising an action-packed finale complete with a police standoff, the return of balaclava men and the discovery of a written note with THAT 'definately' misspelling.
With yet another agonising seven days to wait until the next installment of the crime drama, there are still so many questions that need answering. Here, FEMAIL unpicks the top 18 ahead of this Sunday.
1. Why did Kate and Jo flee after shooting Ryan Pilkington?
Fans expressed their relief on social media after it was revealed Kate survived the tense shoot out in the lorry park at the end of episode five.
It was bent copper Ryan who came a cropper, with firearms trained Kate shooting him twice in the chest.
In a Thelma and Louise-inspired fashion, the two women then fled the crime scene in Kate's service vehicle, after she quite rightly had a go at her colleague for luring her to her death. To buy her trust, Jo took Kate's gun and touched it so that her prints were on the murder weapon - making it look like she killed Ryan.
The pair then abandoned Kate's car before heading to Steve's garage - at which point Kate revealed they have keys to each other's homes for emergencies - and borrowed his motor.
A gripping hunt for the pair commenced, with Carmichael warning officers that the duo were considered to be 'armed and dangerous'. But the question remains, why did Kate do a runner?
It seems strange she'd want to protect Jo after she arranged to have her murdered, and it was even weirder that she was reluctant to surrender at gunpoint when caught.
It certainly cast doubt in some viewer's minds over her intentions, as they couldn't understand why she would run if she lawfully killed Ryan. Her actions even left some wondering if she could be the illusive 'H'.
Surely Kate isn't bent? She's certainly got some explaining to do...
2. What is under the concrete floor at the warehouse?
After she was released from prison, Kate got straight back to work, heading with Steve to the OCG's weapon's workshop which was being combed by forensics.
They were met by DS Chris Lomax - who was reprimanded by Kate for being a 't**' after giving off distinctly frosty vibes towards Steve.
It turned out the OCG had been using the warehouse to workshop firearms, but with the enormous machinery impossible for just two people to move - remember the two OCG members that were shot dead by AC-12 last week? - Kate is suspicious about what they were trying to cover up.
With Lomax poised to call off forensics, she demanded they call out ground penetrating radar (GPR) to find out what's under the concrete floor.
So what does she suspect might be lurking down there? More dead bodies? Or could it be the incriminating evidence they're looking for to uncover the identity of the 'fourth man'?
3. Is Marcus Thurwell really dead?
Fans were stunned last night when it appeared James Nesbitt's character Marcus Thurwell was killed off before he even appeared on screen.
With AC-12 watching via a video link, Guardia Civil police officers stormed his Spanish home and found two bodies on the bed - and judging by the sound of flies, it looked like they'd been there a while.
The police officer leading the raid confirmed the dead man's identity as retired detective chief inspector Thurwell, but viewers weren't given a clear view of his body.
So, was it really him? Some fans are convinced that Thurwell was in fact the Spanish AFO leading the raid on his home, after noticing a likeness between the two men.
Surely an actor of Jimmy Nesbitt's calibre will at least be given a scene... but if he is really dead, who killed him, and why?
4. What more does Jo know - and who did she think was her father?
Jo seemed genuinely stunned when it was revealed her 'uncle' Tommy Hunter is in fact her father. She'd previously told Kate that her mum was Tommy’s sister, while her dad was 'a bent police officer'.
So who did she think her real father was? She revealed her mother, Samantha Davidson - nee Hunter, was raped at 15 and fell pregnant, but she 'never knew the details'.
Samantha was sent to Glasgow under her mother's maiden name - Davidson - where she gave birth and raised Jo until she was 16, at which point Uncle Tommy 'came looking' and ordered his niece to join the police and do his bidding, driving her mother to suicide.
Eagle-eyed viewers last night spotted a grammatical error which they believe could indicate who is messaging Jo.
The typo appeared on a poster on the wall behind Jo, which read: 'Please return all files once your finished with them Thank you!!!!' It should have read 'you're'.
Many connected the grammatical error to the frequent misspelling of 'definitely' as 'definately' by the person giving Jo orders via a chat room on her laptop. Fans believe it may suggest it's the same person who put up the poster in the police station.
If not Tommy, who is the corrupt cop Jo thought of as a father figure? Was she told her mother's rapist was a senior police officer? Or could she have been referring to an adoptive dad who raised her? She certainly looked rattled when presented with a picture of Marcus Thurwell - could it be him?
Jo remained tight-lipped during her interrogation, batting off most questions with a 'no comment'.
She did confirm a few things we'd been wondering about; she admitted it was her who tipped off the OCG about the raid on Ross Turner and set up the decoy to delay arresting Carl Banks, and it was her who planted the burner phones at Farida Jatri's flat and the files in DCI Buckells' car. She was also meant to frame Terry Boyle, but admitted she couldn't go through with it.
But she remained adamant she didn't know anything about the death of Lawrence Christopher while in police custody, or what murdered journalist Gail Vella was looking into.
Was she genuinely in the dark - or keeping quiet out of fear?
5. Is DCS Carmichael bent?
Last night's episode left some fans convinced that Detective Chief Superintendent Patricia Carmichael is 'H' or at the very least involved with the OCG.
Her behaviour during Jo's interview was more than shifty, and she attempted to shut down Arnott and Hastings' questioning whenever they verged on talk of corruption in the force on more than one occasion. She even cruelly revealed Hastings' secret and approaching retirement.
Some viewers even theorised that she was trying to send a message during the 'puzzling' interview based on how often she tapped her pen.
This Morse code theory popped up during Arnott's questioning of Davidson, specifically when he tried to get information about Gail Vella's laptop and computer.
Although Jo remained tight-lipped, Carmichael did seem to start sweating a little as she tapped her pen four times and took a sip of water.
Morse Code is an alphabet that spells out words or messages using a series of short and long sounds, with the officer appearing to make four taps and spell out H.
Carmichael again set alarm bells ringing whens he cut off Hastings at the end of the interview following his knockout question about Chief Constable Philip Osborne (Owen Teale) being H.
Cutting off the AC-12 head's question, she declared that Jo was being charged with 'perverting course of justice and misfeasance in public office'.
Was she trying to wrap things up before Jo landed her in it? Is her takeover of AC-12 all part of a masterplan to thwart their investigation?
6. Will AC-12 really be disbanded?
Earlier in the series, Hastings was dealt the devastating blow that he's being forced into retirement after 30 years, with his AC-12 team set to be disbanded.
DCC Andrea Wise said the force is planning to let 90 per cent of the anti-corruption unit go, and threatened Hastings with disciplinary action if he refused.
So is time really running out for the team to get to the truth? What would happen to Steve and newcomer DC Chloe Bishop?
7. Is DCI Buckells really working with the OCG?
Having been accused of interfering with the investigation into the murder of journalist Gail Vella, DCI Buckells was incarcerated - where he colluded in the murder of bent lawyer James 'Jimmy' Lakewell at the hands of OCG member Lee Banks.
While a bit of a prat, it had seemed throughout the series that Buckells lacked the guile to be a kingpin in the OCG. Though he was involved in the 2003 Lawrence Christopher case – along with Thurwell and Osborne - so he could know something about the cover-up.
It was also Buckells' call to bring in Jo Davidson to lead Operation Lighthouse, and he could also have been behind Ryan's appointment. Was he too being manipulated by the OCG?
However, during her interview Jo revealed she manipulated Buckells into signing off her plan to thwart the surveillance of Carl Banks, suggesting they weren't on the same page. So, is he really guilty of anything other than incompetence? Or, given the golf clubs that were found in his boot, could he be the new caddy?
8. Will DI Steve Arnott get busted by Occupational Health?
Having been ignoring the reminders dropping in his inbox to book an appointment for a routine drugs test, Steve now faces disciplinary action if he doesn't comply.
Trouble is, he's clearly addicted to painkillers, though we haven't seen him pop his pills for a couple of weeks now.
Is he buying himself time while he weans himself off them in order to pass the drugs test? Or is he simply delaying the inevitable and risking being suspended?
9. Will Jo survive in prison?
While Steve is confident that Jo will be safe in prison, after she was put in the vulnerable prisoner unit (VPU) at Brentiss, the ending of last night's show suggested that might not be the case.
As Jo was led to her cell, viewers spotted corrupt prison officer Alison Merchant - who put faeces in Lindsay Denton's food and poured boiling water over her hands in series two - eyeing her up. She also accused Farida Jatri of resisting having handcuffs put on as an excuse to break her wrist.
Merchant looked up towards the CCTV camera, suggesting she's aware she's being watched, but she clearly knows how to turn them off... is she out to silence Jo once and for all?
The trailer for the finale shows Jo leaving the high-security prison in handcuffs, only to end up alone in a van with the corrupt prison officer. Jo says: 'What's going on?', before the camera flashes a sinister look from Merchant. It's not looking good...
10. Where did the cash in Steph's attic come from?
In episode three, Steve is seen paying a visit to Steph Corbett, the widow of undercover agent John Corbett, killed by Ryan Pilkington.
During the last series, it was revealed that Hastings had previously had a close relationship with Corbett's mother, an IRA informer, when he was a young Royal Ulster Constabulary officer in Belfast in the 1970s. Anne Marie was abducted and her body was then found in 2001.
When Hastings found out that Corbett was Anne Marie's son, he took a portion of the cash given to him by Mark Moffat from the Kettle Bell Complex investment deal, and was seen poised to give the cash to Steph after her husband's death.
Steph is then spotted visiting Hastings at the station by Steve at the start of series six, as well as making a number of phone calls to him.
After staying the night at her house, Steve conducts an 'illegal search' and finds an envelope of cash in the attic, which he traces back to OCG money and tells Kate about it.
While she and Davidson are being asked to surrender after their brief stint on the run following Ryan Pilkington's shooting, Kate asks if they're being 'set up' and tells Davidson that Steve has told her some 'bad stuff about the gaffer'.
So did the cash in Steph's attic come from Hastings, and was he simply trying to help out because of his connection to her late mother-in-law, or is there something more sinister at play?
11. Are Jo and Kate more than just colleagues?
At the beginning of the series, fans noticed some definite sexual tension between Kate and Jo, with many championing the idea of a romance.
While Jo is believed to have been in a relationship with a woman - Farida - Kate is straight, having split from her husband (though it's unclear why), but there did seem to be more to their lingering glances, hugs and brief finger touching than simply friendship.
Is there a spark between them, and could this be the reason Jo took the rap for shooting Ryan? Or is one (or both of them) leading the other on to keep them on side?
12. Is DS Chris Lomax hiding something?
Along with Kate and Ryan Pilkington, Lomax (Perry Fitzpatrick) has been working on Jo's MIT squad investigating the murder of Gail Vella.
In epsiode five, Lomax was very reluctant to give up his phone when Kate demanded the team surrender their mobiles to ensure 'complete security on comms' and prevent any leaks about their raid of the OCG workshop.
Some fans also have their suspicions about Lomax after spotting his photo on the AC-12 board alongside mug shots of suspects PS Farida Jatri, Terry Boyle and Carl Banks.
Could Steve and the team already be on to him - hence the tense exchange when they arrived at his forensics scene in last night's episode?
13. Was Steph Corbett trying to drop Steve in it with Hastings?
After discovering Steve's painkiller stash following their night spent together at her house, in episode three Steph called Hastings to tell him he'd paid her a visit.
Steve later returns to Steph's and questions why she spoke to Hastings about her concerns over his medication.
She told him John got involved with drugs in the early days of his career, warning Steve they can 'take over your life'.
If she really was just looking out for him because she cares, why dob him in to his boss and run the risk he could lose his career?
14. Why did Hastings rat on John Corbett?
In last week's episode, Steve visited Lee Banks in prison to get answers about Gail Vella, whom AC-12 believe was murdered by his brother Carl.
Angry at the suggestion that Carl was a rat, he explodes: 'You want to talk about rats, ask your boss,' before revealing Hastings told him there was a rat in the OCG - undercover copper John Corbett.
When Hastings later discovered Corbett was the son of Anne-Marie McGillis last season, he was inconsolable.
It's never been revealed why Hastings blew Corbett's cover - which resulted in him having his throat slit by Ryan Pilkington. It could well be the reason Hastings gave Corbett's widow £50,000.
15. Did Carl Banks actually kill Gail Vella?
He remains the prime suspect, but the murder of Gail Vella is still unresolved - and with Carl Banks dead, it's tricky to prove he was responsible.
The evidence certainly points that way; Vella was investigating police corruption and put in a request to interview several of those in prison, along with Lee Banks, a member of the OCG.
Lee agreed to talk - and two weeks later she was killed. In episode five Steve visited Lee in prison and alleged that he took responsibility to draw out of Vella what she knew, and then told Carl who passed it up the chain of command within the OCG, with the top man giving Carl the order to silence the journalist. However, after he was caught 'shouting his mouth off', Carl was also killed.
While Steve's theory makes sense, could there be another twist in store?
16. Who caused the James Lakewell ambush?
In episode four, AC-12 made a major breakthrough when they discovered Gail Vella talked to corrupt lawyer James Lakewell, who featured in series four and was a university friend of DCI Roz Huntley's husband Nick. He was found to be in league with the OCG and involved in a cover up relating to Operation Trapdoor.
Steve and Chloe visited him in prison, but Lakewell refused to talk on the basis that some prison guards were in league with organised crime.
AC-12 then planned an operation to sneak him out of prison to interview him elsewhere, but were ambushed after someone tipped off the OCG.
Steve presumed it was someone within the prison when they picked him up, but Chloe raised the possibility the leak could have been someone within AC-12.
Her theory was shot down by Hastings, who insisted that wouldn't happen on his watch, but could she be right? Is there a rat within AC-12 who's pulling the strings?
17. Will Steve quit AC-12?
In the first episode of series six, Steve is seen meeting up with an old flame, Nicola Rogerson, who works in serious and organised crime for Central Police and passed information to AC-12 in season two, and revealed he's 'reached the end of the line in anti-corruption' and is 'ready for a new challenge'.
He received an email in episode two offering him a confidential chat with her boss, just after Hastings made him a DI, and asked Nicola to delay his transfer in episode four.
Has this recent case reinvigorated his passion for AC-12? Or will Steve head to pastures new regardless of what happens to the unit under Carmichael?
18. Who is H - aka the 'fourth man'?
Line Of Duty creator Jed Mercurio excited fans when he shared the first clue about the plot of season six to Twitter. Uploading a snap of a packet of the Australian chocolate biscuits TimTams with the caption '#LineofDuty Series 6 Plot Clue No. 1', fans began to ferociously speculate as to what it might mean.
But one plot point hanging over the next season of the show is about the identity of the ominous 'H'.
While the mystery was somewhat answered in the season five finale, it was also revealed that there are FOUR people pertaining to be 'H', with the final one still unknown. So who could it be?
Patricia Carmichael (Anna Maxwell Martin)
She was one of season five's stand-out characters, swooping in towards the end of the series to interrogate Ted Hastings - highly suspected to be 'H' at the time.
And while she simply seemed to be excellent at her job - and hellbent on uncovering the corruption within the department - could it be that Patricia Carmichael was SO keen to pin the blame on Ted to take the focus away from herself.
Could SHE be the fourth 'H'?
Her position of power and respect, along with her unnaturally steely and cut-throat demeanor, could well point to this - and does her strange behaviour during Jo's interrogation.
Ted Hastings (Adrian Dunbar)
Ted Hastings was pinpointed by viewers of the show, as well as the characters on the show, to be a candidate for 'H'.
But it seemed he was exonerated by the end of season five, allowed to walk free.
But could be potentially be triple-crossing us all? Could he in fact STILL be the potential fourth 'H'.
The biggest issue with this theory is that Gill Biggeloe - one of the three revealed to be 'H' - was so against him. Surely she wouldn't be working to deter him if they were in league?
UNLESS, she doesn't KNOW he is the fourth 'H'?
CC Philip Osborne (Owen Teale)
Osborne certainly fits the 'high ranking officer' bill, and has the power to punish anyone who fails to do his bidding.
It seems Ted suspects Osborne, asking Jo during her interrogation if the 'fourth man' is the chief constable.
We were also treated to his 'enemies within' speech during the closing montage - significant? Perhaps...
DCC Andrea Wise (Elizabeth Rider)
Detective Chief Constable Andrea Wise was new to the show in season five and is another high-powered contender for 'H'.
She has been constantly interfering when it has come to supporting AC-12’s investigations, removing them from the investigation into Operation Pear Tree. She also instigated the Ted Hastings investigation.
She is also keen to cover up police corruption, despite announcing at the end of season five: 'This constabulary will work tirelessly to root out rotten apples in its ranks.'
PCC Rohan Sindwhani (Ace Bhatti)
Police and Crime Commissioner Rohan Sindwhani demanded to be 'in on' a meeting between Andrea Wise and Ted Hastings.
This might be a small clue but any clue could be valid at this point.
Any dubious behaviour suggests 'H' is at play, and so Rohan could indeed be culpable - though he was recently thrown under the bus by Chief Constable Philip Osborne.
