Right help for surprise police visit (4)
I believe the answer is:
raid
'surprise police visit' is the definition.
(I've seen this before)
'right help' is the wordplay.
'right' becomes 'r' (common abbreviation).
'help' becomes 'aid' (synonyms).
'r'+'aid'='RAID'
'for' acts as a link.
(Other definitions for raid that I've seen before include "A sudden attack or incursion" , "Rapid surprise attack" , "bust" , "Sudden swift attack" , "Search by police without warning" .)