National treasury (9)
I believe the answer is:
exchequer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">national treasury</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for exchequer that I've seen before include "royal treasury" , "Purse" , "government section" , "large supply of money" , "National treasury" .)