Leading current energy supplier (2,5)
I believe the answer is:
in power
'supplier' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'leading current energy' is the wordplay.
'leading' is a charade indicator (letters next to each other).
'current' becomes 'in' ('in' can mean current or trendy).
'energy' becomes 'power' (synonyms).
'in' next to 'power' is 'IN POWER'.
Can you help me to learn more?
(Other definitions for in power that I've seen before include "Having charge or control" , "Being the government" .)