Lookout, there HAS to be more to it. I can't BELIEVE that anyone would leave the country of their birth because the way they speak is criticized or ridiculed by an ignorant few. MORE likely, he doesn't want to get typecast as an "upper echelons only" actor and feels the need to spread his wings.
April,I can imagine that Benedict is " all things English ",and as the report states,there's a culture of " posh-bashing ",which I've clearly seen on here against Jeremy. No doubt most of the scummy prisoners have had a go at him too for that reason alone too.
It's a well known fact that the Americans love the true Englishman,probably/obviously better than those in our own country do. Such as the series,Downton Abbey which gets far more of an airing in the States than it does here,because of its " Englishness ".
It's rather sad that in this actors' case,that he feels he'll be more welcomed somewhere else other than his own country,but,again,the Americans will welcome him with open arms.
I mean,how a person speaks has got nothing to do with being " posh ".What is " posh " anyway ?