Thanks for the links, mav - some very interesting stuff there. My own observations concur with those of Trudghill, that RP is evolving, rather than disappearing. One still hears it from relatively youthful people on the radio and TV, particularly on Radios 3 and 4 in Britain. However, an individual's lack of RP is no longer a great barrier to being taken seriously, so long as the accent isn't "broad."

I'm immortal until proven otherwise