With Line Of Duty set to return to our screens this weekend, question marks still hang over the closing scenes of series four.
Although ACC Hilton was unmasked as the bent copper known only as H, suspicions were raised that perhaps they got the wrong man as AC-12's Ted Hastings was seen looking shiftily as the final episode drew to a close.
Now the actor who plays Hastings, Adrian Dunbar, has said the scenes weren't in the original script and were added in by creator Jed Mercurio at the last minute.
Speaking to Digital Spy, Adrian revealed: "At the end of the last series there's a couple of very strange looks between myself and Vicky [McClure, who plays DS Kate Fleming], which would suggest there's something going on with Hastings."
I just thought, how dare you? We've gone through six eps and at the end of it you're making me go 'Ooh I'm a bit suspicious!'
He continued: "Those shots weren't in the script. Jed came onto direct that last bit and suddenly he put these last few shots in and you're thinking, what's this he's doing?!"
Adrian said Jed "didn't tell" the cast "anything about it", adding: "That just happened on the last day of the shoot – practically the last thing we shot were those reactions."
With the actor revealing that the identity of H will be explored in series five, he added: "I just thought, how dare you? We've gone through six eps and at the end of it you're making me go 'Ooh I'm a bit suspicious!'"
He added: "I do think Jed knows rather more than he ever tells us, that's for sure!"
This season, Dunbar says Hastings will find himself under scrutiny as his personal life is explored. While Martin Compston, who plays DS Steve Arnott, also promised a "pay-off" in the H storyline.
Vicky McClure has also added intrigue by admitting that her character has a middle name that's never been revealed before – and it's one that could see the mysterious H finger of doubt point at her, too.
She said: "Somebody decided that my character was Kate Helen Fleming – throwing in a middle name I knew nothing about!"
With the new series featuring the villainous Stephen Graham as John Corbett, leader of the deadly Balaclava Men, there are sure to be many twists and turns as Line Of Duty returns to BBC One this Sunday at 9pm.
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