Cook using British fuel (4)
I believe the answer is:
boil
'cook' is the definition.
(boiling is a kind of cooking)
'british fuel' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'fuel' becomes 'oil' (oil is a type of fuel).
'b'+'oil'='BOIL'
'using' acts as a link.
(Other definitions for boil that I've seen before include "Cook, swelling" , "Abscess" , "Sore with a hard core filled with pus" , "become inflamed" , "Cook in hot water" .)