In all your TV-watching and film-viewing history, which non-Scottish actor or actress do you think had a) the most convincing Scottish accent (extra points for a convincing regional Scottish accent) and b) which one had the most cringe-worthy and ridiculous Scottish accent (to at least rank in infamy with Dick Van Dyke’s stunningly ridiculous London Cockney accent in Mary Poppins) ?

What's your top 3 and bottom 3 ?