While a second added: “As a newbie to the #LineOfDuty party I just want to note that Carmichael tapped her pen four times. Seems suspicious, just saying.”
Sadly for viewers, while addressing the theories, Martin told Jonathan Ross: “Do you know what I love about that one? It’s so spot-on, but that line never got said.
“[It] blew my mind. Jed [Mercurio, writer of Line of Duty] said, ‘No, that line never happened’.”
Carmichael has been among the most popular guesses for H, but currently, Philip Osbourne is the most likely, according to betting companies.
Line of Duty comes to a dramatic ending, tonight on BBC One at 9pm.