London borough cut Japanese funds back (7)
I believe the answer is:
hackney
'london borough' is the definition.
(I know that Hackney is a London borough)
'cut japanese funds back' is the wordplay.
'cut' becomes 'hack' (hacking is a kind of cutting).
'japanese funds back' becomes 'ney' (I can't justify this - if you can you should give a lot more credence to this answer).
'hack'+'ney'='HACKNEY'
Can you help me to learn more?
(Other definitions for hackney that I've seen before include "A kind of taxi or car for hire" , "district of London" , "Wear out" , "Carriage for hire" , "draught horse" .)