�Why is the Englishman always the "baddie" in Hollywood movies ?

Ever noticed how the Englishman is always the bad guy in Hollywood movies? It always seems to follow the same formula.First of all the character is introduced as a likable but bumbling English gent who may even appear to be a victim in some way of whatever crime is perpetrated but by the end of the film you have learnt that the charming Englishman is in fact a dastardly swine never to be trusted. This has been happening since talkies first hit the screen. Why is this ? is it a hangover from the war of independence or the Boston Tea Party or something ? And why is it always English and not other Brits such as a Scotsman ? Off course this ruins many American films or TV because as soon as you hear the English accent ( not always a real one ) you just know they did it. Perhaps someone has an explanation, and how many others have noticed this?