Great anger finding vermin in outskirts of Wisbech (5)
I believe the answer is:
wrath
'great anger' is the definition.
(I've seen this before)
'vermin in outskirts of wisbech' is the wordplay.
'vermin' becomes 'rat' (I've seen this in other clues).
'in' is an insertion indicator.
'outskirts of' means to remove the middle letters.
'wisbech' with its middle removed is 'wh'.
'rat' inserted inside 'wh' is 'WRATH'.
'finding' is the link.
(Other definitions for wrath that I've seen before include "Great anger" , "great heat?" , "Failure to keep cool" , "Angry indignation" , "Ire" .)