Bitterness about British book (5)
I believe the answer is:
bible
'book' is the definition.
(I know that book can be written as Bible)
'bitterness about british' is the wordplay.
'bitterness' becomes 'bile' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in BBC).
'bile' placed around 'b' is 'BIBLE'.
(Other definitions for bible that I've seen before include "The Good Book" , "Book regarded as the ultimate authority on its subject" , "Holy books" , "The Christian or Jewish scriptures" , "Book of the Scriptures" .)