Vehicle excise duty (4,3)
I believe the answer is:
road tax
'vehicle excise duty' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for road tax that I've seen before include "Levy on cars etc" , "Fee to run vehicle" , "What drivers pay" , "Levy on vehicles using public thoroughfares" , "Vehicle excise duty" .)