Linked from
The 13 pages that link to Received Pronunciation, each with the reason it gives.
DictionCompared with: It is a specific accent, not a universal standard for good diction.
AccentBroader topic: It is a named accent often treated as a reference variety in English.
DiphthongBroader topic: Its vowel inventory provides familiar examples of English diphthongs.
PronunciationBroader topic: It provides a named reference accent rather than a universal standard.
Terry-ThomasRelated: His carefully projected upper-class speech made social status part of the joke.