When is Line of Duty series 6 on TV? What’s going to happen? Who’s in it?

Jed Mercurio’s bent copper series featuring detectives Ted Hastings, Kate Fleming and Steve Arnott is coming back to screens – with a new guest lead

  We may earn commission from links on this page. Our editorial is always independent (learn more)
Line of Duty S5 - episode 3

As one of the most popular shows on British television, it should be no surprise that Line of Duty is set to return to our screens in the near future.


The BBC One drama following the investigations of police anti-corruption unit AC-12 was commissioned for a sixth series by the BBC before the fifth had even started airing.

However, recent events in the real world have meant that production has hit a rather major snag, meaning fans might have to wait a little longer than planned for the new episodes.

Here’s everything we know so far…

When will Line of Duty be back on TV?

Production started on the new series in February 2020, with BBC One’s official Twitter posting a pic of a beaming AC-12 gang alongside their new nemesis, but things quickly ground to a halt due to the coronavirus outbreak.

The official Line of Duty Twitter account announced on 16th March that filming had been indefinitely suspended to keep the cast and crew safe from COVID-19.

Similarly drastic measures were taken across the film and television industry, as numerous major productions were forced to shut down until further notice.

The following month, star Vicky McClure appeared as a guest on BBC Breakfast, where she gave some insight into the final days on set and revealed that a substantial amount of series six is yet to be filmed.

She said: “We were about six weeks into the shoot of 16 weeks, so we’ve got a long way to go yet.

“The production were brilliant. While we were filming and it was starting to unfold, we were all doing the necessary precautions and being well looked after, and then it just came to a halt. It had to, as did most things.”

In May 2020, creator Jed Mercurio gave an update to fans on The Andrew Marr Show, stating that it was “in doubt” whether Line of Duty would resume filming this year or have to pick back up in 2021.

Given these extraordinary circumstances, RadioTimes.com predicts that Line of Duty series six will air on BBC One in late 2021, allowing extra time for the series to resume production safely.

Before the pandemic hit, the BBC released these first-look filming shots in February, showing the AC-12 gang back at work on the case of crooked coppers.

Line of Duty series 6 filming pictures
Line of Duty series 6 filming pictures
World Productions

Who is the guest star for Line of Duty series 6?

The guest lead for series six of Line of Duty will be Kelly Macdonald, who will play DCI Joanne Davidson, “the senior investigating officer of an unsolved murder, whose unconventional conduct raises suspicions at AC-12”.

Kelly Macdonald

Line of Duty writer and showrunner, Jed Mercurio, said: “We’re honoured that Kelly Macdonald will join Martin, Vicky and Adrian in series six of Line Of Duty. DCI Joanne Davidson will prove the most enigmatic adversary AC-12 have ever faced.”

Macdonald recently starred in The Victim and Giri/Haji. She is also known for her roles in Trainspotting, Gosford Park, State Of Play, No Country For Old Men and Boardwalk Empire.

Who is in the Line of Duty cast?

The main AC-12 actors: Adrian Dunbar (Supt Ted Hastings), Vicky McClure (DI Kate Fleming), and Martin Compston (DS Steve Arnott) are all set to return.

Joining them will be Shalom Brune-Franklin (Our Girl), Andi Osho (Kiri) and Prasanna Puwanarajah (Doctor Foster).

Perry Fitzpatrick will also be part of the cast, having previously appeared opposite Vicky McClure in Channel 4’s This Is England and I Am Nicola.

Line of Duty - series 6 new cast
Line of Duty – series 6 new cast
Don Arnold/WireImage/Michael Tullberg/David M. Benett/Getty Images

It’s also possible Taj Atwal (PC Tatleen Sohota) and Aiysha Hart (Murder Squad cop DS Sam Railston) will make a comeback.

Polly Walker’s character Gill Biggeloe has been given a new identity, which doesn’t entirely rule out a return in season six, but there would have to be some sturdy justification for bringing her back.

Line of Duty S5 - Episode 5
Aiysha Hart as DS Sam Railston

As in previous years, we’re expecting some big name guest stars to join the cast in series, but there have been no official announcements just yet aside from Kelly Macdonald.

And Jed Mercurio is already teasing us with some highly unlikely series six guest stars…

How to watch Line of Duty online

Line of Duty is available to stream now on BBC iPlayer and will remain on the service for a full year.

If you would prefer to own every episode, you can pick up the first five seasons in one handy DVD box set through Amazon UK.

Note: Line of Duty is not currently available on Netflix.

What happened in Line of Duty series five?

You can see a summary of each episode here or read a (spoiler-heavy) synopsis below…

  1. Line of Duty series 5: episode 1
  2. Line of Duty series 5: episode 2
  3. Line of Duty series 5: episode 3
  4. Line of Duty series 5: episode 4
  5. Line of Duty series 5: episode 5
  6. Line of Duty series 5: episode 6

The fifth run of Line of Duty centred on John Corbett (Stephen Graham), a rogue undercover officer who would go to any lengths to catch ‘H’, the corrupt copper at the heart of the Organised Crime Group (OCG).

As the series progressed, we learned that Corbett had links to AC-12 chief Ted Hastings. It transpired that Corbett’s mother, Anne-Marie, was a police informant who had a relationship – professional and perhaps more – with Hastings during The Troubles in Northern Ireland.

Thanks to lawyer Gill Biggeloe – who was secretly in league with the OCG – Corbett believed Hastings was responsible for Anne-Marie’s death at the hands of paramilitary forces. And, again due to Biggeloe, Corbett was determined to prove Hastings was a bent copper.

But his mission was cut short when the OCG discovered Corbett was a rat and slit his throat.

How did the OCG find out Corbett’s true identity? By the end of the series, it still wasn’t clear. According to OCG member Lisa McQueen, Corbett’s cover was blown thanks to a tip-off from Lee Banks, an imprisoned henchman from the same gang.

And where did Banks get this information from? Although never proven, many suspected Ted Hastings was the source. As AC-3 leader DCS Carmichael (Anna Maxwell Martin) theorised, Hastings could have leaked this intel as revenge – earlier in the series Corbett had beaten Ted’s wife.

After a large amount of bribe money was discovered in Hastings’ shabby hotel room, Carmichael then arrested him for conspiring to murder Corbett. And, going further, she intended to prove Hastings was ‘H’. However, this investigation only revealed that Biggeloe was actually trying to frame Ted for everything.

But although Hastings returned to active duty at the end of the series, he’s sadly not completely off the hook just yet…

Series six has been confirmed as taking place 18 months on from the events of the previous series.

Will series six be Line of Duty’s last?

In short: we’re not sure.

In a lot longer: Although the BBC hasn’t commissioned a seventh series, Mercurio certainly appears open to the idea. Rather than outright saying the sixth run would be the show’s last, he told the audience at the BFI & Radio Times Festival that he will be discussing future episodes with the BBC after series five has broadcast.

“Once series five has finished airing we’ll have a conversation with the BBC, with a view to whether there’s a possibility to series seven being commissioned. But we definitely know we’ve got series six,” he said.

Judging from series five viewing figures, a recommission seems likely. Its opening episode drew in a peak audience of over 8 million viewers, with an average of 7.8 million watching the entire episode — that’s larger than the season four finale in 2017.

Who is H?

Not one person, but four. Turns out that AC-12 had misinterpreted the dying testimony of Dot ‘The Caddy’ Cottan: instead of one police Kingpin called ‘H’, there’s actually a quartet of high-ranking police staff working with the OCG.

Looking back at the testimony, Steve Arnott and Kate Fleming noticed that Craig Parkinson’s character was tapping out the Morse code for ‘H’ on his left hand. Combining this signal with Cottan blinking at the letter ‘H’, the AC-12 detectives deduced he wasn’t trying to reveal the identity of one bent copper, but make it clear there’s four in the service.

Dot's dying declaration

In other words, there are four corrupt officers – and they’re NOT necessarily called ‘H’.

How much does this revelation change Line of Duty? At this stage in the show, not a lot. After all, as Fleming outlines, AC-12 has already discovered three of the four ‘H’s (again, just to clarify, their name doesn’t have to start with ‘H’). And they are…

  • DI Matthew Dot Cottan – as known as ‘The Caddy’
  • Lawyer Gill Biggeloe
  • Chief Superintendent Derek Hilton

There’s still one out there, though. As before, AC-12 are on the hunt for one corrupt senior member of the service.

The bad news? It could be anyone – their name doesn’t have to start with ‘H’. The good news? The final ‘H’ maybe isn’t as powerful as was feared – they were just one of four, not a single criminal mastermind.


Where is Line of Duty filmed?

Line of Duty is filmed in Belfast, where the cast relocate during shooting. Series six saw Martin Compston, Vicky McClure and Adrian Dunbar return to the Northern Irish capital, but the cast and crew were released when filming was halted due to coronavirus.