I'm in old city-state without proper approval (10)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

I’M + AT (in) + UR (old city-state) containing [without] PRIM (proper). I didn’t know this word defined by Collins as: sanction, authority, or approval, esp for something to be printed, but I arrived at it eventually via checkers and wordplay.