Does anybody find that since being in the UK (those of you who haven't been here long enough to start developing a British accent) your regional US accent has become stronger?
For example, I have a friend who is an expat from the southeastern US. Before he moved to England, he had a standard American English accent, with just a hint of southern. As he's lived in England, he's started to sound more and more like a character from Gone with the Wind.
I am from Brooklyn, and find myself tempted to say things like ex-cape (escape) and si'in (sitting). I think it could be because there is no pressure to speak standard American English, since it's not standard here anyway, so we revert to the accents we learned from our parents when we were babies.
In terms of English people understanding me, I find that it doesn't make a difference whether I speak in a Brooklyn accent or a standard American TV-announcer accent. It's all foreign to them, either way.