Fictional material kept in Tory organisation (10)
I believe the answer is:
kryptonite
'fictional material' is the definition.
(I know that kryptonite is a fictional material)
'kept in tory organisation' is the wordplay.
'organisation' is an anagram indicator.
'kept'+'in'+'tory'='keptintory'
'keptintory' anagrammed gives 'KRYPTONITE'.
(Other definitions for kryptonite that I've seen before include "threat to Kent" , "Mineral avoided by Superman" .)