Fearless detective's lead at the end is fair game (5,3)
I believe the answer is:
lucky dip
'game' is the definition.
(I know that lucky dip is a type of lottery)
'fearless detective's lead at the end is fair' is the wordplay.
I cannot quite see how this works, but
'detective' could be 'di' (Detective Inspector abbreviation) and 'di' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lucky dip that I've seen before include "Container with articles of various values for random choice" , "Box filled with sawdust hiding prizes" , "Bran tub game" , "Eg, bran tub" , "Game of chance at a fair" .)