Downton Abbey actor dissed fellow cast member as the 'stupidest' in Christendom

Now that you're here, we'll tell you that the actor who plays Tom Branson (Allen Leech, who is as funny as he is adorable) was referring to Isis as "the stupidest dog in Christendom." At 5:40 in the video below:

And I don't know why it has a job. It will not sit where it's supposed to. It's a treat whore... It'll do anything for a treat. But if you don't have treats and you run out and you're in a scene and you're half way through the scene that's only about four minutes long and suddenly this dog gets up, sniffs your crotch and leaves... And Maggie Smith goes, "Can you not control him?"
     No, I can't Maggie. I'm sorry.
     ...Myself and Hugh Bonneville, who plays Lord Grantham, have a plan next year [the interview was from 2013 before the dog was written out of the show] to buy a dog and train it ourselves. It'll be cheaper. We'll take the money — and spend it on cats.

Leech goes on to describe the parlor games the cast plays during dinner scenes, which can last 12-14 hours.