Endeavour star Roger Allam auditioned to play Lewis in the original Inspector Morse

However, Allam has now revealed he was almost part of the original Morse series, revealing that he was once in the frame to star alongside John Thaw as Morse's sidekick Lewis.

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“I've got a feeling, though it might be a wrong memory, that I even went up for the part of Lewis,” Allam told RadioTimes.com on the set of Endeavour’s latest series, explaining that he remembered auditioning for the part of Morse’s sidekick (the role eventually went to Kevin Whately).

“Or at least someone suggested it: my agent at the time or [Thaw’s wife] Sheila Hancock, someone like that.

“I honestly can’t remember,” he laughed. “Maybe I dreamt it!”

In the end, Allam did feature in a later episode of Inspector Morse – he played a university member in 1997’s Death is Now My Neighbour – and decades on, he ended up in a partnership with Endeavour Morse after all, albeit as the senior partner.

In the upcoming sixth series, however, Morse and Thursday are working apart, and Allam says the new situation is taking its toll on the character.

“Everyone's out of where they comfortably are, the characters,” Allam said.

“Things aren't good for anyone. Morse starts off in uniform in Woodstock. And Thursday is at a new station; he's been bumped down a rank, and he's under the command of Box, who's a younger, aggressive Sweeney-type, shall we say.

“He’s tempting Thursday with bribes, with a bung. Obviously he's in a bit of a vulnerable position, and so he's tempted by Box with that – by joining the group of them that do take bungs.

“So things are not good in Thursday land, really,” he concluded.

For his part, Allam said that working without Evans to begin with was “unfamiliar,” which helped him play the changed Thursday.

“It was just unfamiliar, which was good for the portrayal of the scenes really,” he said. “For Thursday it’s unfamiliar, and it's not in his comfort zone. Less easy.”

Hopefully it won’t be too long before the old team is back together. One way or another, Roger Allam always seems to find his way back to Morse eventually.

Endeavour returns to ITV on Sunday 10th February at 8.00pm