Tory politician accepting trustee’s case for cut to commuted offence (8,2,5)

I believe the answer is:
contempt of court
'offence' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'tory politician accepting trustee's case for cut to commuted' is the wordplay.
I cannot really understand how this works, but
'tory' could be 'con' (abbreviation for conservative) and 'con' is present in the answer.
'politician' could be 'mp' (Member of Parliament) and 'mp' is found within the answer.
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is found in the answer.
'trustee' could be 't' (abbreviation) and 't' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for contempt of court that I've seen is " Action showing disrespect of legal processes".)
