It was almost convincing if you'd never heard a real Scottish person,
and didn't notice that the accent jumped at random between Edinburgh, Dublin and North America.

That said, I used to have a teacher whose accent switched between Texan and cockney every few words, so it was not totally implausible.
( The Mock TurtIe ™ --- Thinks you are a cunt, on, Wed 3 Jun 2009, 20:56, archived)

I once went to a lecture by a guy from Bradford
who'd been lecturing in the States for most of his professional career. That was kind of weird and confusing.
( Moon Girl Technologies horrendous beanbag, Wed 3 Jun 2009, 21:02, archived)