News agency since 1851 (7)
I believe the answer is:
reuters
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">news agency since 1851</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 reuters that I've seen before include "International news agency" , "Noted news agency" , "up-to-date agency" .)