All accents get made fun of! lol
The RP accent is the most beautifal accent on the planet in my opinion. The vowel sounds are just perfection. All other english accents around the world are so plain in my opinion. If you want to learn the accent, I recommend this book.
Get Rid of Your Accent: The English Pronunciation and Speech Training Manual: Amazon.co.uk: Linda James, Olga Smith: Books
If you want to learn the older style RP, you will want to study the cardinal vowels. Buy a book on phonetics. This book is great.
A Practical Introduction to Phonetics Oxford Textbooks in Linguistics: Amazon.co.uk: J. C. Catford: Books