According to the Cambridge Dictionary, Received Pronunciation is defined as

"the standard way in which middle-class speakers of southern British English pronounce words".

Received Pronunciation (RP) is an accent of Standard British English that was originally associated with the educated social group in southern England. It is also known as the "Queen's English", "Oxford English", or "BBC English". RP is considered a prestige accent and is widely recognized as a standard of English pronunciation in the UK and other countries.

RP is a historically determined accent that emerged in the late 19th and early 20th centuries, and it was based on the speech of public school-educated individuals and the British upper-middle and upper classes. RP is characterized by its clear, precise pronunciation, and its relatively standardized grammar and vocabulary. Despite being associated with a specific social group, RP has become a widely recognized accent that is considered the benchmark for standard English pronunciation in the UK and elsewhere.

Many aspiring British actors learn RP at acting school, and many famous and notable people speak it within the UK. Look at these Pinterest links to get an idea of British people who speak RP in some form or another. 

Some would also distinguish between the traditional, upper, neutral, and modern forms of RP. We could say that the RP accent has evolved over the years. For example, perhaps the younger members of the royal family, such as Prince William, could be considered to speak with a more modern RP accent. 

There is no "correct way" to speak English, however, Received Pronunciation would be suitable for non-native English speakers who want to speak with an accent that is clear and can be easily understood by others. Those who need to communicate clearly and effectively, such as diplomats, business people, interpreters, and scientists, would benefit from learning RP. 

Key characteristics of RP

Received Pronunciation has a certain set of features that distinguish it from other accents of English. Some of these features include:

• Vowel Sounds: RP has a distinctive set of vowel sounds, including a longer and more open pronunciation of the /ɑː/ sound in words such as "bath" or "dance".

• Consonant Sounds: RP is known for its clear and precise pronunciation of consonants, particularly the /t/ and /l/ sounds.

• Intonation: RP is characterized by its distinct rhythm and melody, with a relatively flat intonation and a consistent stress pattern.

• Grammar and Vocabulary: RP follows standard grammatical rules and uses a relatively standardized vocabulary.

Examples of famous people who are known for speaking Received Pronunciation:

• The Royal Family: Many members of the British Royal Family, including Queen Elizabeth II, have traditionally been associated with RP.

• Actors: Many British actors, particularly those trained in classical theatre, are known for speaking RP. Examples include Benedict Cumberbatch, Maggie Smith, and Helen Mirren.

• Broadcasters: RP has been the accent of choice for many British broadcasters and news presenters such as David Attenborough.

• Politicians: Some British politicians, including former Prime Ministers Margaret Thatcher and John Major, have been associated with RP.

These are just a few examples, and it's worth noting that while these individuals may have used RP in the past or in specific contexts, they may also use other accents or variations in their daily speech. Additionally, many people who are known for using RP have not necessarily had it as their first accent, but have learned it later in life.

Examples of Received Pronunciation can be found by visiting the link below: 

Speakers of RP: British Hollywood Actors