Legendary British king (6)
I believe the answer is:
arthur
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">legendary british king</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for arthur that I've seen before include "See 21" , "Excalibur's owner" , "Dudley Moore film" , "Excalibur king" , "Legendary British king" .)