The most common and most likely answer to this crossword clue is the 10 letter word BUREAUCRAT
I've seen this crossword clue in The Daily Telegraph
B
U
R
E
A
U
C
R
A
T
More clues leading to the result BUREAUCRAT
- Caught miserable-looking specimen on branch, perhaps mandarin
- Official brought up difficulty with area cut in review
- Civil servant caught whistle-blower under desk
- Zealous official flyer injected with preparation of curare and uranium
- Government official about to give away secret behind almirah
- Official’s craftily starting to unravel Arab truce
- Official objection about a cure mixed with radium
- Mandarin, endless stream, a curate translated
Buddy explains!

The straight part
We know that "Mandarin" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mandarin = bureaucrat.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.
What does BUREAUCRAT mean?
BUREAUCRAT noun- An official who is part of a bureaucracy.
- (WMF jargon) A wiki user with the right to change user access levels.