Look back in despair, suffering as Britain is now (9)
I believe the answer is:
polarised
'as britain is now' is the definition.
'look back in despair suffering' is the wordplay.
'look' becomes 'lo'.
'back' is a reversal indicator.
'in' means one lot of letters goes inside another.
'suffering' is an anagram indicator.
'lo' in reverse letter order is 'ol'.
'despair' with letters rearranged gives 'parised'.
'ol' inserted into 'parised' is 'POLARISED'.
(Other definitions for polarised that I've seen before include "Extremely divided" , "Separate" , "like some light" , "in opposing camps" , "(Of light waves) vibrating in one plane" .)