Most of East Anglia redeveloped -- effect of numbers? (9)
I believe the answer is:
analgesia
'effect of numbers?' is the definition.
(things which numb pain cause analgesia)
'most of east anglia redeveloped' is the wordplay.
'most of' means to remove the last letter.
'redeveloped' is an anagram indicator.
'east' with its last letter taken off is 'eas'.
'eas'+'anglia'='easanglia'
'easanglia' with letters rearranged gives 'ANALGESIA'.
(Other definitions for analgesia that I've seen before include "As a linage (anag) - insensibility to pain" , "Absence of pain" , "Painlessness" , "Loss of pain" , "Inability to feel pain" .)