Rise in intensity irritated unmarried actor Paul earlier on (8)
I believe the answer is:
escalate
'rise' is the definition.
(I've seen this in another clue)
'intensity irritated unmarried actor paul earlier on' is the wordplay.
I cannot quite see how this works, but
'irritated' could be 'ate' (something eating at something is irritating them) and 'ate' is present in the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for escalate that I've seen before include "Increase in magnitude" , "Magnify" , "Ramp up" , "mount in tension" , "Cause to increase, say dispute (8)." .)