RP itself has changed over time, as the wp article notes -- if you tried to speak RP of the 1950s you would definitely come across rather strangely today. Some

RP itself has changed over time, as the wp article notes -- if you tried to speak RP of the 1950s you would definitely come across rather strangely today. Some of the arguments over naming the article mentions is I think a disagreement over whether RP should only refer to that upper class style of speech (and thus be a relatively rare accent today) or if it should be used as a name for what some people would label "Standard Southern British".