Last letter in London (3)
I believe the answer is:
zed
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">last letter in london</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 zed that I've seen before include "Z" , "Final letter of alphabet" , "Last letter of alphabet" .)