London has a long and rich history of theater that dates back to late 1500s. It is now widely considered the theater capital of the world, even surpassing New York City. London's West End has something for everyone, and it is no longer just catering to the aristocratic upper class. And it is not just the West End, as the Southbank of London as well as other areas around the country has their theater venues, with the Globe Theater highlighting Southwark.
Such an extensive theater background obviously has been a breeding ground for great acting talent. I personally have done some acting in London and can attest to the fact that the acting talent there is amazing. There are so many avenues these actors can develop their craft that it is a huge industry. So with the number of players that have grown out of this hotbed for acting that is London, should it be any surprise that there are so many British actors getting key roles in American television now?
It has been called the British invasion of television and movie actors. It seems like you can rarely turn on a TV drama series in America now without seeing at least one British actor. There is a perception that British actors are much better trained than their American counterpart, and for the most part this is probably true. In America actors are often trained for a single genre, be it stage, films or television. Perhaps because there is a lot more work in the United States actors have become more specialized.
From a commercial standpoint this might be a good thing, but the typical English actor does everything. They act on a television show, do commercials then move on to star in a film. In between it all they may perform a role on stage. This devotion to their craft comes from not trying openly to be stars, but to take on work wherever it comes. They end up with well-rounded resonances and they take something from each genre that they work in.
Another thing that English actors seem to be able to do better than American actors is their mastery over accents. The variations in the English accents that they have to learn while mastering their craft in the UK has forced them to develop this area of their repertoire. So when they are asked to take on an American accent it's just a matter of fine tuning. Because American actors are not asked to develop this part of their toolbox they have the disadvantage to the British actor of not having that accent range.
So when we watch an American television show with a British actor doing a southern accent, be assured that a great deal of work went in to what we see on the screen.