Shock — southern ladies running riot round prison! (10)
I believe the answer is:
scandalise
'shock' is the definition.
(scandalise can mean to shock or appal)
'southern ladies running riot round prison' is the wordplay.
'southern' becomes 's' (abbreviation).
'running riot' indicates an anagram.
'round' is an insertion indicator.
'prison' becomes 'can' (the can is American slang for prison).
's'+'ladies'='sladies'
'sladies' with letters rearranged gives 'sdalise'.
'sdalise' going around 'can' is 'SCANDALISE'.
(Other definitions for scandalise that I've seen before include "cause sensation" , "Shock by impropriety" .)