Some work by British composer (4)
I believe the answer is:
berg
'composer' is the definition.
(20th Century Austrian composer)
'some work by british' is the wordplay.
'some work' becomes 'erg' (scientific unit of work).
'by' is a charade indicator (letters next to each other).
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'erg' after 'b' is 'BERG'.
(Other definitions for berg that I've seen before include "South African mountain - Austrian composer" , "Alban ----, composer of the incomplete opera 'Lulu' (1935)" , "Lump of ice" , "trouble at sea" , "South African hill - Austrian composer" .)