With drugs around, posh chap exploded (3,3)
I believe the answer is:
set off
'with drugs around posh chap exploded' is the definition.
I can't judge whether this defines the answer.
'with drugs around posh chap' is the wordplay.
'with' is a charade indicator (letters next to each other).
'drugs' becomes 'es' (E is a term for an ecstasy pill).
'around' says the letters should be written in reverse.
'posh chap' becomes 'toff' (I've seen this before).
'es' in reverse letter order is 'se'.
'se' put next to 'toff' is 'SET-OFF'.
Can you help me to learn more?
(Other definitions for set off that I've seen before include "'Leave on a journey (3,3)'" , "Begin journey or explode bomb" , "Begin journey or cause to ignite" , "Leave - explode" , "Display - mount - start journey" .)