The most common and most likely answer to this crossword clue is the 12 letter word PAPER-PUSHER
I've seen this crossword clue in The Times
P
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More clues leading to the result PAPER-PUSHER
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The straight part
We know that "Office worker/newsagent?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case office worker/newsagent? = paper-pusher.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
Crossword Answer definitions
PAPER-PUSHER noun- Clerk or bureaucrat (especially one with a routine job)