RP/BBC English or British English as a standard language
As for its phoneme inventory, Gimson states, that this accent has 20 vowels and 24 consonants. The system of vowels embraces 12 pure vowels or monophthongs: i:, i, æ, Λ, a:, o, o:, υ, u:, з:, ә and 8 diphthongs: ei, ai, oi, әυ, aυ, iә, eә, υә.