I first saw him on Mock the Week a while ago, and found him quite objectionable - he did a skit on the North, and thought that humour was just taking the piss out of the Northern accent. As he's quite well-spoken, it came across as snobbish and smug, more than funny. It didn't help that he practically pissed himself after he did it, like it was the funniest thing in the world.
But frankly, I've seen him in loaRAB of other things recently, and I've really warmed to him. I actually find him hilarious now.