Official permission to write verse? That stretches the truth (6,7)
I believe the answer is:
poetic licence
'that stretches the truth' is the definition.
(licence to be untruthful in art)
'official permission to write verse?' is the wordplay.
'official permission' becomes 'licence' (I've seen this before).
'to' says to put letters next to each other (I've seen this in other clues).
'write verse?' becomes 'poetic' (I am not sure about this - if you are sure you should believe this answer much more).
'licence' put after 'poetic' is 'POETIC LICENCE'.
(Other definitions for poetic licence that I've seen before include "Departing from accuracy for artistic effect" , "Excuse for rule-breaking" , "that might be endorsed by grammar police?" , "Justifiable departure from the conventional" , "A taking of liberties" .)