Cockney thief (3,4)
I believe the answer is:
tea leaf
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cockney thief</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tea leaf that I've seen before include "Cockney crook" , "Part of plant used to make drink" , "Ingredient of infusion - thief (rhyming slang)" , "might be spotted in China" , "source of drink?" .)