Firm having to restrict Corbynite principles? (5)
I believe the answer is:
credo
'principles?' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for credo that I've seen before include "I believe in Latin" , "Dogma" , "Statement of faith" , "music in church" , "Decor (anag.)" .)