Johnson or Morrison
I believe the answer is:
van
I believe this clue is a double definition.
'johnson' is the first definition.
(I've seen this in another clue)
'morrison' is the second definition.
(musician Van Morrison)
(Other definitions for van that I've seen before include "Truck with an enclosed cargo space" , "Leading unit at the head of an army" , "Leading point of army" , "Trade vehicle" , "Leading part" .)