Line of Duty's 'challenging' season 7 explained - including questions that need answering

When we return to AC-12 in season seven, the unit has been disbanded and rebranded the Inspectorate of Police Standards. The synopsis continues: "Anti Corruption work has never been more difficult and in this challenging climate Steve Arnott, Kate Fleming and Ted Hastings are assigned their most sensitive case so far."

Creator Mercurio remained tight-lipped about the plot in his statement, which read: "Everyone involved in Line Of Duty feels enormous gratitude to the show's fans. We're privileged to have had so many of you follow the ups and downs of AC-12 over six previous seasons and we couldn’t be more delighted to be returning for a seventh."

He added: "Corruption in this country is supposed to have come to an end while Line Of Duty was off air so I've been forced to use my imagination."

As for the show's release date, given filming starts in spring, the earliest we might expect the new season is late 2026. It's more likely that the show will arrive in 2027. 

Martin Compston, Vicky McClure and Adrian Dunbar will reprise their roles as AC-12's finest Steve Arnott, Kate Fleming and Ted Hastings, respectively. Further casting details have yet to be announced. 

Fans can look forward to the introduction of a new character, Detective Inspector Dominic Gough, whose casting has not yet been revealed. DI Gough is described as a "a charismatic officer winning plaudits for a string of takedowns of organised crime", who is accused of "abusing his position of trust to act as a sexual predator". The synopsis asks: "But is Gough's case a deliberate distraction from a bigger threat still operating in the shadows?"

Martin Compston described the role as a "job of a lifetime". "Not only in terms of the show's success but the people I've had the opportunity to work with I now call some of my closest friends. I can't wait to pull the waistcoat on again and get the team back together," he said. 

Meanwhile, Trigger Point star Vicky McClure said: "It goes without saying I'm so excited Line Of Duty is back! Can't wait to work with Jed, Martin and Adrian again. Belfast, we'll see you soon!"

Northern Irish actor Adrian Dunbar added: "As we count down the AC-12 days of Christmas what a joy it is to know that the Three Amigos will be back filming together next year. Delighted with the news and looking forward to those mercurial twists and turns."

While the season six finale finally unveiled DSU Ian Buckells (played by Nigel Boyle) as 'H', we've still got some questions that need answering. 

Firstly, is Buckells really 'H'? This bombshell revelation proved to be anticlimactic for many viewers, who were a little surprised that this minor, recurring character was unveiled as the mysterious criminal mastermind AC-12 had spent a great deal of time and effort hunting down. Even Adrian Dunbar said Buckells is just a "distraction". "He's not 'H'. We just got the guy we could actually pin a charge on. We didn't get 'H', we got Buckells, the patsy," he previously told RadioTimes. 

Secondly, will James Nesbitt return? In season six, the actor made a brief cameo as Marcus Thurwell, who appeared in a photograph and was later revealed to be one of the dead bodies found by the Spanish authorities. Is James's appearance simply a brief cameo or will he make a surprise return?

Finally, is Ted Hastings corrupt? Yes, AC-12's commanding officer managed to explain his way out of the infamous 'definately' misspelling, saying he was posing as 'H' after studying the OCG messages, but he's come under suspicion numerous times over the years and are we totally convinced that he's not bent? While it appears as though Hastings remains the moral compass of AC-12, Mercurio isn't afraid to shock viewers with a major twist.