Deplores old City business tax (9)
I believe the answer is:
execrates
'deplores' is the definition.
(execrating is a kind of deploring)
'old city business tax' is the wordplay.
'old' becomes 'ex'.
'city' becomes 'ec' (the City of London postcode).
'business tax' becomes 'rates'.
'ex'+'ec'+'rates'='EXECRATES'
(Other definitions for execrates that I've seen before include "Hates" , "Curses" .)