Required Ms Platell to reject a party that she supports (9)
I believe the answer is:
mandatory
'required ms platell to reject a party that she supports' is the definition.
'mandatory' can be an answer for 'required' (I've seen this in another clue). I'm unsure of the rest of the definition.
'party that she supports' is the wordplay.
I cannot really see how this works, but
'party' could be 'tory' and 'tory' is located in the answer.
'she' could be 'manda' and 'manda' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mandatory that I've seen before include "Compulsory" , "allowing no option" , "Obligatory" , "Not optional" , "required" .)