Old PM Theresa married still (3)
I believe the answer is:
may
'old pm' is the definition.
(Theresa May)
'theresa married still' is the wordplay.
I cannot really understand how this works, but
'married' could be 'm' (abbreviation, e.g. in genealogy) and 'm' is found in the answer.
'still' could be 'ay' (archaic term for 'always') and 'ay' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for may that I've seen before include "Could" , "Hawthorn blossom" , "Month; hawthorn" , "Girl's name; 10 ac (anag.)" , "UK PM" .)