MP's area (12)
I believe the answer is:
constituency
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mp's area</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 constituency that I've seen before include "MP's electors" , "parliamentary seat" , "MP's area" , "District represented by MP" , "Division of country for voting purposes" .)