Inquisitor in call for truce on island (6)
I believe the answer is:
paxman
'inquisitor in call' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'for truce on island' is the wordplay.
'for truce' becomes 'pax' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'island' becomes 'Man' (the Isle of Man is an example).
'pax'+'man'='PAXMAN'
Can you help me to learn more?
(Other definitions for paxman that I've seen before include "Jeremy - - (TV)" , "He interviews" .)