Old royal articles worn by police at one time (9)
I believe the answer is:
anastasia
'old royal' is the definition.
'anastasia' can be an answer for 'royal' (daughter of Tsar Nicholas II of Russia). I'm not sure about the 'old' bit.
'articles worn by police at one time' is the wordplay.
I cannot quite understand how this works, but
'articles' could be 'anas' (ana are collections of information like an article) and 'anas' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'time' could be 't' (abbreviation) and 't' is located in the answer.
The remaining letters 'asa' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for anastasia that I've seen before include "Grand Duchess, daughter of Tsar Nicholas II" , "Russian princess thought once to have survived the revolution" , "Russian royal" , "Titled Russian" , "Bolsheviks dispatched her" .)