Received Pronunciation, often known as BBC English, is:
Received Pronunciation, or RP for short, is the instantly recognisable accent often described as ‘typically British’. Popular terms for this accent, such as ‘The Queen’s English’, ‘Oxford English’ or ‘BBC English’ are all a little misleading. The Queen, for instance, speaks an almost unique form of English, while the English we hear at Oxford University or on the BBC is no longer restricted to one type of accent. RP is an accent, not a dialect, since all RP speakers speak Standard English.
To gain practice with the sounds of RP, try the resources at this site. To hear some examples of it in action, listen to these two clips featuring and Stephen Fry Joanna Lumley: