The Peep Show comedian accepted that he had probably ruined his chances of winning a role in ITV's period drama after complaining in one of his Soapbox videos that it had "tipped over the line" of plausibility.
Asked if his comments had caused outrage amongst Downton fans, Mitchell told Metro: "Not that I've noticed. Maybe people slagged me off and I haven't been Googling myself assiduously enough.
"I think it's terribly written but still enjoy watching it and I don't know why. I'll watch and think, 'No-one would say that, why's that happening?' Maybe the enjoyment of the sets and costumes is enough to sustain it."
He continued: "I'd love a part in it, but I've probably shot myself in the foot there."
Mitchell also confessed to harbouring ambitions in Hollywood, but said that he is "too much of a stick-in-the-mud" to leave Britain for good.
"If someone offered me a lucrative job, there's no doubt I would take it," he said. "But I don't want to move there. I'm too much of a stick-in-the-mud to want to live anywhere so sunny."
Downton Abbey's third series continues this Sunday (October 14) at 9pm on ITV1.