Police line (6)
I believe the answer is:
cordon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">police line</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 cordon that I've seen before include "Line of guards to prevent entry" , "A ring of police or military" , "Police line; trained fruit tree" , "Circle of policemen" , "Line of guards; rope" .)