PM wanting perfect garden (4)
I believe the answer is:
eden
This clue is a double definition.
'pm' is the first definition.
(former prime minister Anthony Eden)
'perfect garden' is the second definition.
(I've seen this before)
'wanting' acts as a link.
(Other definitions for eden that I've seen before include "Idyllic garden" , "late PM" , "(Biblical) paradise" , "The first garden" , "happy state" .)