Stop talking to leader of union supporting Conservative grandee (3,3)
I believe the answer is:
cut off
'stop' is the definition.
(cutting off is a kind of stopping)
'talking to leader of union supporting conservative grandee' is the wordplay.
I cannot really see how this works, but
'to' is found in the answer.
'leader' could be 'f' (I have seen 'German leader ' mean 'f' so perhaps 'leader' could also mean 'f') and 'f' is located in the answer.
'union' could be 'u' (common abbreviation as in Trades Union Congress) and 'u' is found within the answer.
'conservative' could be 'c' (UK political abbreviation) and 'c' is present in the answer.
A single letter 'f' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for cut off that I've seen before include "Disconnect" , "Sever connection with, keep from contact" , "Put phone down on" , "Disinherit c" , "Leave nothing to in will - not a penny" .)