Interjection from an ancient king (3)

I believe the answer is:

tut

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'ancient king' is the definition.
(King Tut)

I can't explain the rest of the clue.

(Other definitions for tut that I've seen before include "Exclamation of disapproval or annoyance" , "Show disapproval" , "Annoyed exclamation" , "Exclamation of rebuke, usually doubled" , "in short I don't like that!" .)

I've seen this clue in the Evening Standard.

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