Acting Detective Superintendent Joanne Davidson, played by Scottish actress Kelly Macdonald, is one of those suspects.
Kelly told the PA news agency even she did not know about a pivotal twist about her character’s parentage until halfway through filming.
The Trainspotting star, 45, told the PA news agency even she did not know about a pivotal twist about her character’s parentage until halfway through filming.
She said: “Jed Mercurio, man, he is troublesome. He keeps a lot to himself. I feel like Martin (Compston, co-star), pictured right, always heard about things first. I felt like he would get the lay of the land.
“I don’t know if that was just because he is so on top of everything and understands everything acutely and what the connotations are.
“I didn’t have the full story on Jo. I just knew that things hadn’t been great for her. Jed kept saying, ‘She is this enigmatic figure’ and he was being enigmatic himself.
“By the time we came back after the first lockdown I knew what was up.”
Speaking about which stars know the identity of H, she added: “The main cast know. I don’t know about everybody. H knows who H is… Like I said, I don’t know the whole cast, but I know the top cast.”
Despite a number of revelations about Davidson linking her to criminal groups, Macdonald said she believed her to be a good person – “I think she has got a good core. I really do,” she said.
The Line of Duty series final airs on BBC One and iPlayer on Sunday at 9pm.
Meanwhile, the two lines I have used myself from time to time are: Lord save us and keep us in wee dugs and She has two chances, a dug’s and nane.
If you can think of a name for the wee donkey, drop us an e mail at firstname.lastname@example.org