Illegal substance CIA once concocted (7)

I believe the answer is:

cocaine

'illegal substance' is the definition.

'cia once concocted' is the wordplay.
'concocted' is an anagram indicator.
'cia'+'once'='ciaonce'
'ciaonce' anagrammed gives 'COCAINE'.

(Other definitions for cocaine that I've seen before include "Recreational drug" , "Number" , "Drug, crack" , "Charlie" , "Strange oceanic narcotic" .)

I've seen this clue in The Times.

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