Most people would probably agree that best buddy and best friend are interchangeable terms.
What do you mean by "in British" ? Do you mean "in English" ? If so the answer is "best friend". Slang terms include (best) buddy and mate.
Friend. If i say your my buddy then im saying your my friend
It can either mean he loves you as your best friend or he loves you like more than friends.
Buddy Companion Best friend Soul mate Mate
miles is my best buddy
Best friend or buddy.
Her best friend is Demi Lovato.
home boy means like best friend or buddy or just someone that you play with or are always with them
It is slang or gangsta for kid or buddy.
a friend you have sex with
a friend
You (buddy, friend, pal) were scrubbing