Fiddle carried by Menzies Campbell (4)
I believe the answer is:
scam
'fiddle' is the definition.
(I've seen this before)
'carried by menzies campbell' is the wordplay.
'carried by' indicates a hidden word.
'SCAM' is hidden in the letters of 'menzies campbell'.
(Other definitions for scam that I've seen before include "Fraudulent action" , "A slangy swindle or fraud" , "Racket" , "Hoax" , "Swindle (Slang)" .)