Model Conservative facing interior reshuffle (9)
I believe the answer is:
criterion
'model' is the definition.
(thesaurus)
'conservative facing interior reshuffle' is the wordplay.
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'facing' says to put letters next to each other.
'reshuffle' indicates an anagram.
'interior' with letters rearranged gives 'riterion'.
'c'+'riterion'='CRITERION'
(Other definitions for criterion that I've seen before include "Touchstone" , "Judging standard" , "Standard by which to judge" , "Benchmark - standard" , "Standard by which something can be judged" .)