Received Pronunciation (RP) is a term used to refer to the socially dominant form of pronunciation of British English. Spoken by less than 4% of people in England, it is associated with educated speakers, particularly those from the southeastern region, including London. RP is often considered the accent of the upper class, and has traditionally been widely used in broadcasting and is associated with prestige and authority.
The features of Received Pronunciation include:
Non-rhoticity: The "r" sound is not pronounced at the end of words or before consonants. For example, "car" is pronounced as "cah."
Lack of regional features: RP is characterized by the absence of specific regional accents or dialectal features.
It's worth noting that the prominence and influence of RP have declined over time, and there is now a greater acceptance of various regional accents and pronunciation styles in the UK. Nonetheless, RP still maintains its association with prestige, education, and traditional British cultural norms. In fact, you may hear reference to 'conservative' RP, and 'modern' RP as the accent has modernised over time.
Most importantly, RP is a minority accent spoken by a very small number of people in a small country and there is no logical reason why anyone anywhere should be striving to achieve this pronunciation in their English.