Berkshire public school (4)
I believe the answer is:
eton
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">berkshire public school</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for eton that I've seen before include "Posh college" , "Town on the Thames noted for its school" , "Public school near Windsor" , "Famous English public school" , "Public school (sounds like 20)" .)