Police force surrounding drug rendezvous (4)
I believe the answer is:
meet
'rendezvous' is the definition.
(I know that rendezvous is a more specific form of the action meet)
'police force surrounding drug' is the wordplay.
'police force' becomes 'met' (short for Metropolitan Police Service).
'surrounding' means one lot of letters goes inside another.
'drug' becomes 'e' (E is another name for ecstasy).
'met' enclosing 'e' is 'MEET'.
(Other definitions for meet that I've seen before include "Fitting - encounter" , "sporting occasion" , "Hunting gathering" , "See 24" , "club" .)