Warning! This article contains Line Of Duty spoilers of the highest order.
Fans of the hit BBC cop drama will remember the character – portrayed by James Nesbitt – was killed off in the penultimate episode of the most recent series, despite viewers having ever only seen him in photographs on the show.
Thurwell was found dead as Spanish police carried out a raid on his home in the hunt for the so-called “fourth man”, who was later revealed to be DSU Ian Buckells.
However, many speculated at the time that Thurwell might actually be dead, despite a line of dialogue during a scene at AC-12 confirming his fate in the finale.
Daniel, who played series three antagonist Sergeant Danny Waldron, admitted he is one of those who believes the theory.
During an appearance on This Morning on Monday, Daniel told hosts Holly Willoughby and Phillip Schofield: “I don’t think James Nesbitt is dead, I don’t know this, but I have a sneaking suspicion he might be the main man.”
Holly agreed: “It makes sense, otherwise you’re like, what was that scene when he was dead on the bed?”
Daniel said: “We didn’t get a close up did we of his bush.”
“And why waste him? What was the point?” Phillip said.
Daniel said, however, that he wouldn’t be surprised if writer and creator Jed Mercurio was trying to trick fans, given Daniel’s own character met a grisly end very early on into series three.
He said: “James Nesbitt is a phenomenal talent but maybe it’s just Jed Mercurio dangling the carrot, who knows. I wouldn’t put it past him. He killed me off didn’t he, he could do anything.”
While “H”, aka “the fourth man”, was revealed in the final episode of series six, many fans are convinced there’s more to the storyline – including Adrian Dunbar, who plays Superintendent Ted Hastings.
A number of questions still remain about Chief Constable Philip Osborne, who previously worked on a team with Thurwell.
Jed Mercurio previously revealed there’s potential to explore Osborne and possible links to organised crime should Line Of Duty return for a seventh series.
Speaking to Den Of Geek, he said: ”[Osborne]’s someone who retains high office who is an outright liar and has been involved in corruption in the past in terms of the Karim Ali case and the Lawrence Christopher case.
“Clearly there would be potential there if we wanted to explore it, but it’s too early to say whether we ever would.”
Actor Owen Teale, who plays Osborne, also issued a plea to Jed to write more episodes so he can “sort out” his character.
The entire Line Of Duty boxset is available to stream on BBC iPlayer. This Morning airs weekdays at 10am on ITV.