Guilty of being in the wrong (2,5)
I believe the answer is:
at fault
This clue is a double definition.
'guilty' is the first definition.
('at fault' can be similar in meaning to 'guilty')
'being in the wrong' is the second definition.
(I've seen this before)
'of' is the link.
(Other definitions for at fault that I've seen before include "In the wrong" , "Rightly taking the blame" , "Guilty" , "To blame, culpable" , "To blame, responsible for mistake" .)