Result of police no longer getting firm backing (5)
I believe the answer is:
occur
'result' is the definition.
(I know this)
'police no longer getting firm backing' is the wordplay.
'police no longer' becomes 'RUC' (Royal Ulster Constabulary, disbanded police force).
'getting' is a charade indicator (letters next to each other).
'firm' becomes 'co' (a firm is a company).
'backing' says the letters should be written in reverse.
'ruc'+'co'='rucco'
'rucco' in reverse letter order is 'OCCUR'.
'of' is the link.
(Other definitions for occur that I've seen before include "exist" , "Befall" , "Spring to mind" , "Go on" , "Come to pass" .)