Prisoner must trot up to bend (7)
I believe the answer is:
contort
'bend' is the definition.
(thesaurus)
'prisoner must trot up' is the wordplay.
I cannot quite see how this works, but
'prisoner' could be 'con' (abbreviation for 'convict') and 'con' is found in the answer.
an anagram of 'trot' is 'tort' which is within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Another definition for contort that I've seen is " Twist out of shape".)