Awfully cruel about politician’s collapse (7)
I believe the answer is:
crumple
'collapse' is the definition.
(I know that crumple is a more specific form of collapse)
'awfully cruel about politician's' is the wordplay.
'awfully' is an anagram indicator.
'about' means one lot of letters goes inside another.
'politician' becomes 'MP' (Member of Parliament).
'cruel' with letters rearranged gives 'crule'.
'crule' enclosing 'mp' is 'CRUMPLE'.
(Other definitions for crumple that I've seen before include "Become crushed" , "Crease" , "Fold, collapse" , "Go to pieces" , "Become creased and wrinkled" .)