Capital city of Belgium (8)
I believe the answer is:
brussels
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">capital city of belgium</span>' is the definition.<br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for brussels that I've seen before include "Union's base" , "Release pent-up energy" , "From which many regulations" , "European Commission HQ" , "sprout?" .)