London cops tell what you owe (3,4)
I believe the answer is:
the bill
'london' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for the bill that I've seen before include "Soap" , "requested at end of meal?" .)