Legal team's dull spiel axed, no one having turned up (11)
I believe the answer is:
prosecution
'one having turned up' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for prosecution that I've seen before include "Accusation of guilt in court" , "Lawyers acting for the crown" , "Bringing of criminal action" , "one side of suit" , "Legal proceedings" .)