Best British tea brewed (4)
I believe the answer is:
beat
'best' is the definition.
(I've seen this before)
'british tea brewed' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in BBC).
'brewed' indicates an anagram.
'tea' anagrammed gives 'eat'.
'b'+'eat'='BEAT'
(Other definitions for beat that I've seen before include "Strike; rhythm" , "Conquer" , "Pound - defeat" , "Rhythmic music unit" , "Strike; pulsate" .)