Ruler found in Buckingham Palace! (4)

I believe the answer is:

king

'ruler' is the definition.
(king is a kind of ruler)

'in buckingham palace' is the wordplay.
'in' indicates the answer is hidden within the clue.
'KING' is hidden in the letters of 'buckingham palace'.

'found' is the link.

(Other definitions for king that I've seen before include "Mythical monarch commemorated by 1" , "Supreme ruler" , "Chess piece" , "Recipient of 10 21 [VELODROME GOLD]" , "Martin Luther -" .)

I've seen this clue in The Telegraph.

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