City drugs impress northern people with their properties (10)
I believe the answer is:
landowners
'people with their properties' is the definition.
'city drugs impress northern' is the wordplay.
'city' becomes 'la' (Los Angeles).
'drugs' becomes 'downers' (downer is a kind of drug**).
'impress' is an insertion indicator (impress can mean enlist or recruit).
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'la'+'downers'='ladowners'
'ladowners' going around 'n' is 'LANDOWNERS'.
(Other definitions for landowners that I've seen before include "lairds, perhaps" , "People involved with deeds" .)