In all probability it’s nearly lunchtime? (3,2,3)
I believe the answer is:
ten to one
This clue is a double definition.
'in all probability' is the first definition.
(I've seen this before)
'nearly lunchtime?' is the second definition.
(shortly before lunchtime at one o'clock)
'it's' acts as a link.
(Other definitions for ten to one that I've seen before include "time?" , "Most likely" , "In all probability" .)