Viewers will remember no-nonsense DCS Carmichael from series five, where she was brought in as an independent investigator from AC-3 after suspicions mounted over the integrity of Superintendent Ted Hastings.

Now with Ted’s forced retirement looming, is Carmichael in position to take control? And with the restructure of the anti-corruption units, is this the end of AC-12?

Anna Maxwell Martin says: “Pat’s back, I can’t remember what she’s doing there, nor would I be allowed to blab, but suffice to say she’s got some new clobber and she’s ready to bust some balls."

Line of Duty is made by World Productions for BBC One and BBC iPlayer. Executive producers are Jed Mercurio, Simon Heath for World Productions and Tommy Bulfin for BBC One. The series is made with support from Northern Ireland Screen and ITV Studios internationally distribute.

Line of Duty airs on Sunday nights at 9pm on BBC One and BBC iPlayer. Series one to five and series six so far are available on BBC iPlayer.