Might it be breakfast time in prison? (8)
I believe the answer is:
porridge
I believe this clue is a double definition.
'might it be breakfast' is the first definition.
(porridge is often served as breakfast)
'time in prison?' is the second definition.
(porridge is a slang term for time in prison)
(Other definitions for porridge that I've seen before include "Boiled oatmeal or prison sentence" , "Morning oats" , "Oat dish; time in prison (slang)" , "Breakfast dish - spell in prison" , "Stir" .)