Seaside town is obliged to defend police operation (8)
I believe the answer is:
hastings
'police operation' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'seaside town is obliged to defend' is the wordplay.
'seaside town' becomes 'sting' (I can't justify this - if you can you should believe this answer much more).
'is obliged' becomes 'has'.
'to defend' indicates putting letters inside.
'sting' put inside 'has' is 'HASTINGS'.
Can you help me to learn more?
(Other definitions for hastings that I've seen before include "Ten Sixty-Six battle" , "Town in East Sussex" , "East Sussex seaside resort" , "Ten sixty six battle" , "Not a good place for Harold" .)